Cut Polska kielbasa in 4 inch pieces. Split lengthwise, 3/4 through. Fill each with mixture of 2 tablespoons grated Swiss cheese and either 1 tablespoon sauerkraut or pizza sauce. Wrap with bacon slices. Secure with toothpicks. Grill or broil 4 inches from heat until bacon is turn, turning often. Service on toasted buns.