Unroll one tube of crescent dough into one long rectangle; seal seams and perforations. Press onto the bottom of a greased 13-in. x 9-in. baking dish. Bake at 375° for 8-10 minutes or until golden brown.
Layer with half of the cheese and all of the corned beef. Combine sauerkraut and salad dressing; spread over beef. Top with remaining cheese.
On a lightly floured surface, press or roll second tube of crescent dough into a 13-in. x 9-in. rectangle, sealing seams and perforations. Place over cheese. Brush with egg white; sprinkle with caraway seeds. Bake for 12-16 minutes or until heated through and crust is golden brown. Let stand for 5 minutes before cutting