Combine the garlic, onion, paprika, oregano, pepper and salt in a small bowl. Sprinkle half the spices over the chicken. Turn the chicken pieces over and sprinkle the remaining spices over them. Rub the spices into the chicken, if needed, to coat well.
Heat a nonstick grill pan over medium heat. Drizzle with the olive oil. Place half the chicken in the grill pan, making sure there is a gap between the pieces. Cook the chicken without touching it for 5 minutes. Flip the pieces over and cook for 3 to 5 minutes until they’re cooked through. Repeat with remaining chicken.
Preheat oven to broil.
Place an oven rack 6 inches from the top of the oven. Put a wire rack over a large baking tray and arrange the chicken on the wire rack. Place the chicken in the oven and broil for 6 minutes. Remove the chicken from the oven, turn each piece of chicken over, and then broil for 5 to 6 minutes.
Let the cooked chicken rest for 5 minutes before serving. Sprinkle the pieces with cilantro, if desired.