1. Cut each chicken breast, pineapple, pepper and onion into approximately twenty-four 1-inch-thick pieces.
2. Combine chicken, pineapple juice, garlic, soy sauce and oil in a large nonmetallic bowl; marinate in refrigerator for at least 1 hour and up to 24 hours.
3. Preheat grill. Lightly coat vegetables with cooking spray.
4. Thread 2 pieces of pepper, pineapple, chicken and onion onto each of 8 skewers. Brush with marinade. (Note: If using wooden skewers, soak in water to prevent charring.)
5. Grill over medium-hot coals until chicken is completely cooked, about 8 to 10 minutes, turning kebabs every 2 minutes so they're cooked evenly on all sides.
Yields 2 kebabs and 1/2 cup rice per serving.