Place all of the marinade ingredients into your food processor or blender. Pulse until the cilantro is broken up into small pieces.
Place chicken thighs into a food storage bag or glass container. Pour the marinade over top of the thighs, turning them so each side is well covered. Seal the bag or the container and place in the fridge. Marinate for at least 2 hours or up to 24 hours.
When you're ready to grill your chicken, preheat your grill to medium high heat (about 450-500 degrees Fahrenheit). Brush a high-heat oil like canola or vegetable oil over the grates.
Place the marinated chicken thighs directly on the grates and grill for 6-7 minutes per side, or until the chicken has developed nice grill marks and releases easily from the grill. Use a meat thermometer to verify that your chicken is cooked when its internal temperature is 165 degrees Fahrenheit.
Remove the chicken to a plate, cover with foil, and rest for 5-10 minutes before serving. Top with fresh cilantro as a garnish before serving, if desired.