Shred the corned beef. In a small bowl, combine the sour cream,mustard, and horseradish. Add one teaspoon of salt and add pepper to taste.
Cook the waffle fries according to package directions.
On an oven-safe serving platter or a baking sheet, spread the fries in an even layer.Cover the fries evenly with the corned beef. Top with the cheeses and bake for 15 minutes or until the cheese is bubbly and just starting to brown.
Evenly sprinkle with the peppers, sauerkraut, green onions, and the remaining black pepper, Drizzle with the sour cream-musatrd sauce and serve immediately.