Combine cilantro, olive oil, adobo seasoning, cayenne pepper, paprika, and kosher salt in a gallon size plastic bag. Add chicken and marinade for at least three hours.
Preheat a grill to medium heat. You could also use your oven, preheated to 400 degrees.
Alternate sliding the chicken, peppers, and onion onto metal skewers. Discard remaining marinade.
Grill for 4 minutes on each side. Enjoy!