In a small bowl, mix all of the dressing ingredients together and set aside.
To assemble each sandwich: Spread each slice of bread with 1 T. of Russian dressing. On one slice of bread, dressing side up, place 2 oz. of sliced corn beef, flowed by 1 oz of Swiss cheese and up to ΒΌ c. sauerkraut. Top with another slice of bread, dressing side in. Repeat to make 4 sandwiches. Heat large skillet over medium heat. Spray skillet with oil. Place 2 sandwiches at a time in the skillet and grill until golden brown on both sides and the cheese is melting.
The Rachel sandwich is a variation on the standard Reuben that substitutes pastrami or turkey for the corned beef and coleslaw for the sauerkraut.