Place sauerkraut in a strainer and drain out as much liquid as possible, pressing on the kraut with the back of a spoon. Then, place kraut in a clean dish towel and squeeze out the remaining liquid and place in a small bowl.
Chop the corned beef into shaving-sized pieces. Place in a small bowl.
Grate the gruyere cheese. Place in a small bowl.
Fill a small bowl with water and put aside.
Place one egg roll wrapper flat on work surface.
Spoon roughly two tablespoons of the corned beef onto the bottom third of the wrapper.
Spoon 1 tablespoon of gruyere over the corned beef.
Sprinkle 1 tablespoon of the sauerkraut over the corned beef and cheese.
Take the bottom of the wrapper and fold over the corned beef.
Fold the sides in toward the middle, and roll the rest of the way down the wrapper.
Using a finger and dip it into the water, then run along with end of the wrapper to secure the seam.
Place egg roll on baking sheet and cover with the damp dish cloth. Continue and assemble and roll the rest, keeping all under the damp towel as you go.
Place one liter of oil in a Dutch oven and heat to 375 degrees.
Fry the egg rolls until cooked through and golden brown, 3-4 minutes.
Drain on drying rack, dabbing with paper towels if necessary.
Serve warm with homemade thousand island dressing!