01 - In a large mixing bowl, combine olive oil, lime zest, lime juice, chopped cilantro, chili powder, smoked paprika, ground cumin, garlic powder, onion powder, salt, black pepper, and cayenne pepper (if using). Whisk until thoroughly blended.
02 - Place chicken breasts into the marinade, ensuring each piece is well coated. Cover and refrigerate for a minimum of 20 minutes and up to 2 hours for enhanced flavor.
03 - Set grill or grill pan to medium-high heat and allow to preheat thoroughly.
04 - Remove marinated chicken from the bowl, allowing excess marinade to drip off. Place chicken on grill and cook for 6 to 7 minutes on each side, or until an internal temperature of 165°F is reached and juices run clear.
05 - Transfer chicken to a cutting board and let rest for 5 minutes. Slice and serve garnished with fresh lime wedges and chopped cilantro.