In a large bowl, combine olive oil, minced garlic, smoked paprika, oregano, thyme, cayenne pepper, salt, black pepper, lemon juice, and lemon zest. Mix well to create a marinade.
Add the chicken thighs to the marinade, ensuring they are well-coated. Cover the bowl with plastic wrap and refrigerate for at least 2 hours, preferably overnight for maximum flavor.
Preheat your grill to medium-high heat. Remove the chicken from the marinade and let any excess marinade drip off.
Place the chicken skin-side down on the grill. Cook for 6-8 minutes, then flip and grill for another 6-8 minutes, or until the internal temperature reaches 165°F.
Remove the chicken from the grill and let it rest for 5 minutes before serving.