Preheat broiler and cut baked potatoes in half lengthwise. Using a spoon, make a shallow trough in cut side of potato to hold filling, leaving at least a ¼" border around edges. Be careful not to take too much potato out, just enough to keep filling from sliding off.
Brush potatoes with butter, season lightly with salt and pepper. Turn potatoes over and butter and season the skin side. Place them on a baking sheet, skin side up and broil 2–3 minutes until starting to brown. Turn potatoes over and broil 2–3 minutes more then remove from oven.
Sprinkle 1 cup of shredded Swiss cheese evenly among the potato skins. Broil about 2 minutes more until cheese is melted then remove from oven.
Meanwhile, pour about 2 Tbsp liquid from the bag or can of sauerkraut into a medium-sized skillet. Heat on low and add the corned beef to one side of the skillet and the sauerkraut to the other half. Heat until warmed through. Do not overheat or the beef will dry out.
Divide warm corned beef and sauerkraut among the potatoes. Top with remaining cheese and broil about 1 minute until cheese is melted. Remove from oven and garnish with Thousand Island dressing. Serve warm and enjoy!
One Last Thing
Make these skins bite-sized by using new potatoes!