Remove the outer skins from the onions and trim off the ends.
Slice each onion into 1/4-inch thick slices (Do not separate the slices).
Coat the grill with cooking spray and preheat for 5 minutes. In a small bowl, combine the barbeque sauce, pepper and Tabasco sauce. Place the onion slices in the grill and smooth 1 teaspoon of sauce over each.
Grill for approximately 5-6 minutes or until tender-crisp. Remove from the grill and repeat the process with remaining onions.