Using a fork, pierce sausage casings several times. In a skillet over medium high heat, brown sausages, turning frequently, about 8 minutes. Set aside.
Using the slicer/shredder disc, slicing side up, slice peppers and onion. Place in 2 quart baking dish. Add oregano and oil; stir to mix.
Place sausage on peppers. Bake at 350°F for 45 minutes. Serve peppers and sausage with noodles or spoon onto toasted sub rolls.
Note: Designed for full-size food processors with a minimum of 6 cup capacity.