Heat oil in a large skillet over medium-high heat. Add peppers and onion; cook, stirring occasionally, until softened, about 4 minutes. Add beef and cook, stirring to crumble, until lightly browned, about 5 minutes. Season with garlic and Italian seasoning and cook, stirring constantly, until fragrant, about 1 minute. Stir in tomato sauce, water, hoagie spread, and salt.