Put a chunk or small handfull of apple wood or cherry wood on the coals before putting chicken on the grill.
Place chicken on the grill, skin side up. Cook for 20 minutes, then flip skin side down. Finish with the skin side up for 20 minutes. Cook for 1 hour or until the skin starts to become slightly crispy.
Remove the butchers twine. Heat the grill to medium high heat. Grill over medium to high direct heat, turning every 1-2 minutes until the skin is nice and crispy
Cooking time can vary depending on the size of thighs. Check internal temperature for 165 F if needed.