1On a medium-size microwave-safe dinner plate, mound corned beef in 2 piles. Top each pile of meat with the sauerkraut. Micro-cook, uncovered, on 100% power (high) 3 to 4 minutes or till heated.
2Top each pile with a cheese slice. Cook, uncovered, on high 1 to 2 minutes more or till cheese is melted.
3Meanwhile, place toasted bread on individual plates. Spread one side of bread slices with salad dressing or mustard. To serve, use a wide spatula to transfer each mound of meat to the dressing side of 2 bread slices. Top with remaining bread slices, dressing-side down.