Preheat the oven to 325°F. Grease an 8½ x 4½-inch loaf pan with nonstick spray.
In a large bowl, stir together the grated zucchini, oil, eggs, and vanilla extract.
Whisk the sugar into the zucchini mixture until the sugar completely dissolves and the mixture is creamed together.
In a separate bowl, sift together the flour, salt, cinnamon, baking soda, and baking powder.
Add the sifted dry ingredients to the wet ingredients. Stir just until combined. The batter should be smooth, with the exception of the shredded zucchini.
Transfer the batter to the prepared pan and smooth the top.
Bake for about 60-65 minutes, or until the bread springs back when gently pressed in the center and a toothpick inserted in the center comes out clean.
Let the loaf cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely before slicing.