Heat oil in a large, deep skillet over medium-high heat. Add sausage slices and cook until browned, about 5 minutes. Remove sausage and set aside.

Add sweet potatoes and half the water to the skillet; boil for 5 minutes. Stir in the sausage, apples, remaining water, sugar, and cinnamon. Season with salt and pepper; reduce heat to medium. Cover and cook, stirring occasionally, until potatoes are soft, 10 to 15 minutes. Serve hot.