Heat olive oil in a skillet over medium heat. Add the sausage and cook until browned on all sides, about 10-12 minutes. Remove from skillet and slice into pieces.

In the same skillet, add sliced bell peppers, onion, and garlic. Sauté until the vegetables are tender, about 5-7 minutes.

Return the sliced sausage to the skillet with the vegetables. Season with salt, black pepper, oregano, and red pepper flakes. Stir to combine and cook for an additional 5 minutes.

Serve hot, optionally with crusty bread or over pasta.