In a large bowl, whisk together the minced garlic, lime juice, olive oil, cumin, paprika, salt, black pepper, and red pepper flakes (if using).
Add the chicken breasts to the marinade, ensuring they are well coated. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
Preheat your grill or a grill pan over medium-high heat.
Remove the chicken from the marinade and let any excess marinade drip off. Discard the remaining marinade.
Grill the chicken for about 6-7 minutes on each side, or until the internal temperature reaches 165°F and the chicken is cooked through.
Remove the chicken from the grill and let it rest for 5 minutes before slicing.
Garnish with fresh cilantro before serving.