In a 2 quart saucepan filled halfway with water and 1 teaspoon salt, boil potatoes 20 minutes, just until fork tender. Remove from heat and cool. Cut into 1/2-inch cubes, leaving skins on, and set aside.
Place prepared peppers on the bottom of a baking dish. Sprinkle evenly with salt and pepper, covering the inside of the peppers.
In a large bowl, mix ground beef, cooled cubed potatoes, onion, 3 Tablespoons of the prepared canned sauce, seasoned salt and Cajun seasoning. Mix well with a wooden spoon and spoon filling over prepared peppers in baking dish, filling insides of peppers and spooning any remaining filling into the dish.
Pour remaining prepared sauce over the top, spreading to cover.
Cover and cook in a 350 degree oven for 1 hour, or until potatoes are tender and beef is thoroughly cooked.
Sprinkle cheese evenly over top and let set for 5 minutes before serving, allowing cheese to melt.