Make the marinade by combining in a medium bowl the garlic, 2 tablespoons cilantro, olive oil, 2 tablespoons lime juice and salt.
Add the chicken to the marinade bowl and toss gently to coat the chicken with the marinade. Put the chicken in the refrigerator to marinate for about an hour.
Make the salsa: Toss the onion and green pepper with 1 tablespoon olive oil, and spread on a grill pan.
Place the onion and peppers on the grill. Grill for 10 to 15 minutes, stirring occasionally. Remove from grill when the onion has started to brown. NOTE: If you don’t have a grill pan for the onion and peppers, you could grill larger onion and pepper slices and chop them after grilling.
In a bowl, combine the pineapple, grilled onion and green pepper, jalapeño pepper, 1 tablespoon olive oil, cilantro and lime juice. Salt and pepper to taste, stir and set aside.
Get the chicken ready to grill by shaking off the excess marinade, reserving the extra marinade in the bowl. Put the chicken on the grill, flipping the chicken after about 5 minutes.
Brush the chicken with the extra marinade after flipping it to help keep the chicken moist. The chicken takes about 10 to 12 minutes total grilling time to be ready, depending on the thickness of the chicken. Check the chicken for doneness after 10 minutes of grilling time, returning to grill for a few more minutes if necessary.
When the chicken is full cooked, remove the chicken from the grill. Plate the chicken topped with plenty of pineapple salsa and enjoy!