1. Preheat grill to 350° to 400° (medium-high) heat. Cut chicken into 1-inch cubes. Thread chicken, onion, and tomatoes alternately onto skewers, leaving a 1/4-inch space between pieces. Sprinkle kabobs with Smoky Barbecue Rub.
2. Grill kabobs, covered with grill lid, 4 to 5 minutes on each side. Serve with White Barbecue Sauce.
Smoky Steak Barbecue Kabobs: Substitute 2 lb. top sirloin steak, trimmed, for chicken. Proceed with recipe as directed.