In a large bowl, whisk together the olive oil, lime juice, honey, minced garlic, cumin, paprika, salt, black pepper, and cayenne pepper (if using) until well combined.
Add the chicken breasts to the marinade, ensuring they are fully coated. Cover the bowl with plastic wrap and refrigerate for at least 1 hour, or up to 4 hours for more flavor.
Preheat your grill to medium-high heat.
Remove the chicken from the marinade and let any excess drip off. Discard the marinade.
Place the chicken on the grill and cook for about 6-7 minutes per side, or until the internal temperature reaches 165°F.
Once cooked, remove the chicken from the grill and let it rest for 5 minutes before slicing.
Garnish with fresh cilantro before serving.