COMBINE oil, garlic salt, pepper and ginger in large resealable plastic bag. Add chicken; seal bag. Turn bag over several times to evenly coat chicken with the oil mixture. Refrigerate 30 min. to marinate.

PREHEAT grill to medium-high heat. Remove chicken from marinade; discard marinade. Grill chicken 15 min., turning occasionally. Brush lightly with some of the barbecue sauce. Continue grilling 4 to 5 min. or until chicken is cooked through, turning and brushing frequently with the remaining barbecue sauce.

PLACE chicken on serving platter; sprinkle with the onions.