ABOUT 45 MINUTES BEFORE SERVING: Place phyllo on waxed paper; cover with slightly damp paper towels to prevent phyllo from drying out. Place 1 sheet of phyllo (16x12-inch) on work surface; brush with some melted butter or margarine; cover with second sheet of phyllo; brush with melted butter or margarine. Slice sheets lengthwise in half to make 2 strips. Place 1 strip on top of the other, buttered-side up.
Preheat oven to 375 degrees.
Drain and rinse sauerkraut; pat dry with paper towels. Place 1/6th of corned beef at end of strip. Spread 1 t. Russian dressing over corned beef; top with 1/6th of Swiss cheese and 1/6th of sauerkraut.
From corned beef end, fold one corner of phyllo strip diagonally over filling so that the short edge meets the long edge of strip, forming a right angle. Continue folding over at right angles, being careful to hold filling securely inside phyllo, until you reach the end of the strip to form a triangular package.
Place package, seam- side down, in 15x10-inch jelly-roll pan; brush with butter or margarine. Repeat with remaining phyllo and filling to make 6 turnovers in all. Bake turnovers 20 minutes or until golden.