Prepare the Marinade: In a large mixing bowl, whisk together olive oil, lime juice, minced garlic, chopped cilantro, cumin, paprika, salt, black pepper, and red pepper flakes (if using) until well combined.
Marinate the Chicken: Add the chicken thighs to the bowl, ensuring each piece is thoroughly coated with the marinade. Cover and refrigerate for at least 15 minutes, or up to 2 hours for deeper flavor.
Cook the Chicken: Heat a large skillet over medium-high heat. Once hot, add a teaspoon of oil to the pan. Place the marinated chicken thighs in the skillet and cook for 5-6 minutes per side, or until the internal temperature reaches 165°F (74°C) and the exterior is slightly crispy.
Serve: Transfer the cooked chicken to a serving dish. Garnish with additional fresh cilantro and a squeeze of lime juice, if desired.