Rinse fish, pat dry. Spray both sides of fish w/ cooking spray. Preheat grill to medium. Place fish over heat on grill. Grill about 6 min, turning once, or until fish flakes easily. In bowl, stir together mayonnaise and lemon juice. Add slaw mix and toss to coat well. Toast bread. Spoon cabbage mix onto each slice of bread, top w/ fish fillet. Drizzle w/ BBQ sauce.