Take a large non-stick skillet pan and coat with non-stick spray. Turn heat to medium setting. Put whole sausages in the skillet until browned on all sides. Remove and set aside. Drain pan.
Spray pan generously with non-stick spray and place onions in pan with salt and pepper to taste. Sauté on medium heat for 5 minutes. Place pepper slices in pan with onions and sauté for 5 more minutes.
While peppers and onions are cooking, slice the sausage into 3/4 inch thick slices. Add the sausage slices to the pan with the onion and pepper mixture.
Then add the can of crushed tomatoes, the Italian seasonings and crushed red pepper flakes. Simmer over a low flame for 20 minutes. Serve the sausage and peppers over a cup of brown rice and a side green salad with a fat-free dressing.