Heat oven to 425. In a large, non-stick skillet, brown ground beef over medium heat 8-10 minutes or until no longer pink. Pour off grease. Stir in corn, barbecue sauce, scallions or onions and salt. Heat through. Place bread or crust on baking sheet. Top evenly with beef mixture. Sprinkle with cheese. Bake 12-15 minutes or until cheese melts. Cut into 6 wedges.