Combine sauerkraut and dressing; set aside.
Scrub baking potatoes and pierce with a fork. Arrange about 1 inch apart on a large microwave-safe plate. Microcook on 100 percent power (high) for 12 to 18 minutes or until tender, turning the potatoes after 6 minutes. Remove from oven. Cover with foil and let stand 6 minutes. Using a sharp knife, cut an "X" in top of each potato.
Top potatoes with half of the sliced cheese, the sauerkraut mixture, and corned beef. Top with the remaining sliced Swiss cheese.
Return the potatoes to the oven and microcook for 3 to 4 minutes more or until cheese melts and mixture heats through, giving dish a half-turn once. Makes 4 servings.