Preheat oven to 425°F. Spread 2 teaspoons dressing on each bread slice; cut slices into quarters. Place bread pieces in a single layer on 2 baking sheets. Bake 9 to 11 minutes or until bread is lightly toasted, rotating baking sheets half way through baking.
Meanwhile, cut cheese slices into quarters; cut each quarter diagonally in half to form 32 triangles. Top bread pieces evenly with Corned Beef, cheese slices and sauerkraut.
Heat appetizers in 425°F oven 3 to 5 minutes or until cheese is melted. Top evenly with remaining Thousand Island dressing.