Make a cross cut in frankfurters on both ends. Separate.
Heat a skillet, add bacon and stir until bacon is cooked, not browned. Drain in paper towel. Add onions to skillet with bacon fat and cook until crystal clear. Remove to a separate bowl.
Place bacon in a saucepan with onions. Add pineapple juice, red peppers, brown sugar, mustard and ketchup. Bring to a boil to reduce. Add frankfurters and cook over low fire until cut ends open. Season to taste. Cover saucepan and turn off heat.
Dilute 1 tablespoon cornstarch in ¼ cup cold water, bring sauce to a boil and stir in cornstarch gradually, to thicken.