SPREAD cut sides of rolls evenly with mustard; set aside.
MIX onion, green pepper, vinegar and hot pepper sauce in large skillet. Cook and stir on medium heat 4 minutes or until onion and green pepper are tender. Divide vegetable mixture evenly between bottom halves of rolls.
PLACE bologna in same skillet; cook on medium-high heat 3 minutes or until lightly browned on both sides, turning over after 1-1/2 minutes. Place 1 bologna slice over vegetable mixture on bottom half of each roll; cover with top halves of rolls.