In a large measuring cup or in a jar with a lid, whisk (or shake) together the lime zest, lime juice, olive oil, garlic, honey, kosher salt, black pepper, cumin, and red pepper flakes until completely combined.
Place the chicken and cilantro in a large Ziploc bag or bowl. Pour the marinade in the bag with the chicken and cilantro; toss gently to combine. Seal the top of the bag and place the chicken in the refrigerator to marinate for at least 30 minutes (or up to 8 hours).
Remove the chicken from the bag or bowl and discard the marinade.
Preheat a grill to medium-high heat (about 400-450°F). Place the chicken directly on the grill grates and grill until the internal temperature in the thickest part of the chicken reaches 165°F, about 6-7 minutes per side for thighs or 10-12 minutes for larger, thicker boneless chicken breasts.