Cucumber Tomato Onion Salad

The freshest summer produce in one bowl! This cucumber tomato onion salad pairs ripe garden tomatoes, crisp cucumbers, and fresh basil with zesty red onion and a simple vinaigrette. It stirs together in minutes for an easy side that goes with just about anything off the grill!

Before You Get Started

Here’s what makes the difference between a forgettable bowl and one your family fights over:

• Use ripe, in-season tomatoes. A pale, mealy winter tomato will tank the whole salad. Save this one for late spring through early fall, when garden, farmer’s market, or vine-ripened tomatoes are easy to find.
• Dress lightly, then add more. You might not need all of the vinaigrette. Start with about half, toss, taste, and add the rest only if needed.
• Let it sit before serving. A 30-minute rest mellows the onion, softens the cucumbers, and pulls the tomato juices into the dressing. Don’t skip it.

How to Make Cucumber Tomato Onion Salad

This salad comes together with basic pantry ingredients and whatever the garden gives you. From start to toss, it’s about 10 minutes of work:

Step 1: Slice the Vegetables

Core the tomatoes and slice them into wedges, scooping out the seeds with your fingers so the salad doesn’t turn watery. If you’re using cherry or grape tomatoes, just halve them. 

Slice the cucumbers into half-circles (English cucumbers don’t need peeling thanks to their thin skin; regular cucumbers should be peeled first since the skin can be tough and bitter). 

Thinly slice the red onion.

Step 2: Combine in a Large Bowl

Toss the tomatoes, cucumbers, onion, and fresh basil together in a large bowl. Snip the basil with kitchen scissors right over the bowl so the leaves stay bright green and don’t bruise.

Step 3: Whisk or Shake the Dressing

In a small bowl or a jar with a lid, whisk or shake together the olive oil and red wine vinegar. The dressing is intentionally simple, since the goal is to highlight the produce, not cover it up. 

With only two dressing ingredients, the quality matters: pick a fruity extra-virgin olive oil if you have it.

⇢ Red wine vinegar is the classic choice, but apple cider vinegar, champagne vinegar, or balsamic vinegar all work. Skip white vinegar, since the flavor is too sharp for a simple salad like this.

Step 4: Dress and Season

Pour about half the vinaigrette over the vegetables and toss to coat. 

Season with kosher salt and freshly ground black pepper, taste, and add more dressing only if it needs it. A heavy pour will leave the salad oily and the vegetables overdressed.

Step 5: Marinate for 30 Minutes

Let the salad sit at room temperature for at least 30 minutes (or up to an hour) before serving. The onions mellow, the cucumbers soak up the dressing, and the tomatoes release their juices into the bowl. 

If you prefer a colder salad, marinate it in the fridge instead.

⇢ Make it Mediterranean: Crumbled feta, diced fresh mozzarella, or small mozzarella balls turn this into something closer to a Greek-style salad. A handful of pitted kalamata olives is a nice addition too.

Step 6: Garnish and Serve

Just before serving, finish the salad with additional fresh herbs if you like (dill, parsley, thyme, oregano, and chives all work well). 

What This Goes With

This salad is a side, so it goes with just about anything coming off the grill. It’s a natural with burgers and barbecue, where the acid in the vinaigrette cuts through the richness of grilled meats.

Storage

Store: Leftover salad keeps in an airtight container in the refrigerator for up to 3 days, though it’s best within the first 24 hours. After a day or so, the cucumbers soften and the salad loses its crunch.

Make ahead: You can prep this up to 1 hour before serving for the best texture. If you need to make it further ahead, slice the vegetables and whisk the dressing separately, then toss everything together about 30 minutes before the meal.

Frequently Asked Questions

What dressing variations work for cucumber tomato onion salad?

The classic version is red wine vinegar and olive oil, but it’s flexible. Apple cider vinegar, champagne vinegar, or balsamic vinegar all swap in well. A squeeze of fresh lemon juice in place of some of the vinegar adds bright citrus flavor. 

For a shortcut, about ½ cup of a good store-bought Italian dressing works in place of the homemade vinaigrette. Skip white vinegar, which has a flavor that’s too harsh for the simple ingredients.

What type of cucumber works best?

English cucumbers are my first pick. The skin is thin (so no peeling required) and the seeds are small, which keeps the salad from getting watery. Persian cucumbers work well too. 

If you’re using regular grocery-store cucumbers, peel them first and scoop out the seeds, since the skin can be tough and the seeds add extra moisture.

Can I add protein to make this a meal?

Yes. A drained, rinsed can of chickpeas turns it into a satisfying vegetarian entrée. Crumbled feta or diced fresh mozzarella adds a creamy, Mediterranean-style finish. Grilled chicken, shrimp, or chickpeas all stretch this from a side into something closer to a main, especially for a light summer lunch.

More Fresh Summer Salads

• Easy Fruit Salad
• Tomato Salad with Basil and Balsamic
• Summer Corn Salad
• Potato Salad
• Classic Pasta Salad