Prep the marinade: In a bowl, whisk together BBQ sauce, honey, lime zest, lime juice, garlic, olive oil, soy sauce, chili flakes, cumin, salt, and pepper.
Taste and adjust with a pinch more salt or lime if needed.
Trim the chicken: Pat the chicken dry. If using breasts, pound them to an even thickness (about 3/4 inch) so they cook evenly.
Marinate: Add chicken to a zip-top bag or shallow dish and pour in about two-thirds of the marinade. Reserve the remaining third for basting and finishing.
Marinate for at least 30 minutes, or up to 6 hours in the fridge.
Preheat the grill: Heat to medium-high (about 400–425°F). Clean the grates and oil them lightly to prevent sticking.
Grill the chicken: Shake off excess marinade and place chicken on the hot grates. Cook 5–7 minutes per side for thighs, 4–6 minutes per side for breasts, depending on thickness.
Baste and caramelize: During the last 2–3 minutes, brush the reserved marinade over the chicken.
Let it bubble and thicken, but watch closely so the sugars don’t burn.
Check doneness: Use an instant-read thermometer. Target 165°F in the thickest part. Remove to a plate and rest 5 minutes.
Finish and serve: Brush with a little more reserved sauce if you like. Sprinkle with chopped cilantro and serve with lime wedges.