Thinly slice the onions and bell peppers. Slice the smoked sausage into ¼"-thick medallions. Heat the olive oil in a large skillet over medium heat. Add the sliced sausage and sauté until browned. Drain off the excess fat.

Add the sliced onions and bell peppers to the skillet. Continue to sauté until the onions are soft and transparent.

Add the diced tomatoes (with juices), oregano, salt & pepper, and the cooked rice. Stir until evenly combined and allow to heat through (5-7 minutes). Taste and adjust the salt if needed. Serve topped with chopped parsley.