1.Preheat The Oven'S Broiler And Set The Oven Rack About 6 Inches From The Heat Source. 2.Stir The Sauerkraut, Mustard, Barbeque Sauce, And Hot Pepper Sauce In A Microwave Safe Bowl. Cook In The Microwave On High Until Slightly Bubbly And Thickened, About 3 Minutes. Meanwhile, Place The Bread Onto A Baking Sheet, And Top With The Roast Beef And Sauerkraut Sauce. Place A Slice Of Cheese Over Each Sandwich. 3.Broil In The Preheated Oven Until The Edges Of The Bread Are Slightly Blackened, And The Cheese Is Bubbly, About 3 Minutes.