1. In 12-inch skillet over medium heat, heat sausages and water to boiling. Cover; simmer 5 minutes. Remove cover; continue cooking, turning sausages frequently, until water evaporates and sausages are well browned on all sides, about 20 minutes. Remove sausages to paper towels to drain. Cut sausages into 1/2 inch-thick diagonal slices; set aside.
2. Meanwhile, thinly slice cabbage. Cut green and red peppers into 1/4 inch-thick slices.
3. In drippings remaining in skillet over medium heat, cook cabbage, peppers, and salt, stirring occasionally, until vegetables are tender, about 20 minutes. Add sliced sausages to vegetable mixture; heat through.
4. Preheat broiler if manufacturer directs. Slice Italian bread horizontally in half. Place bread halves, cut side up, on cookie sheet; broil 3 minutes or until bread is lightly toasted.
5. Spoon sausage-and-vegetable mixture onto bottom half of bread; replace top half. Cut sandwich crosswise into 4 pieces.