Heat large nonstick skillet over medium heat until hot.
Add onion, cook 3 to 5 minutes until golden brown.
Add Ground Beef and bell pepper; cook 8 to 10 minutes, breaking beef into ½-inch crumbles and stirring occasionally.
Stir in tomato sauce, barbecue sauce, ketchup, Worcestershire sauce, brown sugar and mustard; increase heat to medium-high.
Bring to a boil; cook 5 to 10 minutes or until sauce is thickened, stirring occasionally.
Season with salt, as desired.
Divide beef mixture evenly among buns.
Top with pickles, coleslaw and cheese, if desired.
Close sandwiches.
