Heat 1 tablespoon olive oil in large skillet over medium heat. Add onions, season with 1/4 teaspoon each salt and black pepper and cook, covered, stirring occasionally, 8 minutes. Uncover skillet and add sliced peppers. Cook, stirring occasionally, until golden brown and very tender, 6 to 8 minutes more; transfer vegetables to a bowl.
STEP 2
Wipe out the skillet and heat remaining tablespoon oil over medium-high heat. Season steak with 1/2 teaspoon each salt and black pepper and cook, tossing occasionally, until browned and cooked through, 3 to 4 minutes.
STEP 3
Lay cheese over the steak; cover and cook until cheese melts, about 2 minutes. Remove from heat and gently fold cheese into steak. Form sandwiches with hoagie rolls, steak mixture, and onions and peppers.