Preheat oven to 350 degrees F. Combine sausage and sauerkraut in large bowl; form mixture into approximately 40 1-inch balls. Place on ungreased baking sheet; bake 15 minutes. Drain on paper towels; cool slightly.
Increase oven temperature to 400 degrees F. To prepare dough, combine cheese, flour, butter, mustard and caraway seeds, if desired; mix well. Press 2 tsp. of dough firmly around each sausage ball. (Dough handles easiest when warm.) Bake on ungreased baking sheet 15 minutes or until light golden. Serve hot with spicy brown mustard for dipping, if desired. Refrigerate leftovers.