In a skillet over medium high heat, spray nonstick spray, then add peppers and onions; saute for 5-6 minutes or until tender, remove and set aside. Spray skillet again, then add sausage slices and cook for 5-7 minutes, stirring often. Add marinara sauce and oregano to skillet, and stir to combine. Lower heat to low, then cook for 3 minutes. Remove from heat.
Arrange rolls into a baking dish coated with nonstick spray. Add green peppers and onion mixture to each roll, then top with sausage and sauce mixture; repeat for all rolls.
Arrange cheese over the top of each hoagie, then sprinkle additional oregano over the top of the cheese.
Place hoagies into oven, and cook for 5-10 minutes, watching closely and removing when cheese is melted and browning.
This is a great recipe to add your favorite vegetables to; mushrooms and zucchinis would be wonderful!