Boil water in a pot. Slice kielbasa into 1/2 inch slices. Chop all bell peppers and onions into bite size pieces. Mince garlic.
Heat oil in large saute pan. Saute garlic and kielbasa for 10 minutes on med-low heat. Toss in bell peppers and onion. Toss pasta into boiling water. When bell pepper kielbasa mixture is 1/2 way cooked, pour in jar of tomato sauce.
Drain cooked pasta. Mix into bell pepper kielbasa mixture for about 10 minutes. Sprinkle Kraft Shredded Mozzarella Cheese right before serving. Season with salt and pepper. Serve with favorite bread and salad.