In a wide skillet, heat oil. Add bananas and cook, turning once or twice, until lightly browned. Remove from pan and drain on paper towels.
Remove oil from the pan except for about 2 tablespoons. Add onions and garlic and cook until softened.
Add pork and cook, stirring occasionally, until lightly browned.
Add vinegar and continue to cook, without stirring, for about 2 to 3 minutes.
Add soy sauce and water and bring to a boil, skimming scum that may float on top.
Lower heat, cover and cook for about 30 to 40 minutes or until meat is tender.
Add sugar and stir until dissolved.
Season with pepper to taste.
Add carrots and cook for about 1 to 2 minutes or until tender.
Add Chinese sausage and bananas and cook until heated through. Season with salt to taste.
Continue to cook until pork is fork-tender and sauce is reduced. Serve hot.