Heat a large skillet over medium-high heat. A Dutch oven also works great!
Break the sausage into small pieces and add to the skillet. If the sausage is lean you might want to add a splash or two of oil.
Sauté for 5 minutes, stirring often, until the sausage is done and is lightly browned.
Break up any big pieces as the sausage cooks.
Remove to a paper towel-lined plate.
Add peppers and onions to the skillet.
Cook 5 minutes, stirring often, until just starting to soften. The moisture from the onion should be enough to keep the mixture somewhat wet, but if not, add a splash of oil.
Add the sausage back to the skillet and stir.
Add the garlic, black pepper, oregano, and marinara sauce. Stir.
Reduce heat to low and let cook 2-3 minutes or until the mixture is warmed through.
Toast the hoagie rolls.
Spoon the sausage mixture into the rolls.
Top with the cheese.
Transfer sandwiches to the oven on a baking sheet and bake until the cheese is melted.