Preheat oven to 350 degrees and spray a 9x13 baking pan with cooking spray.
Slice rolls in half and place the bottom halves in prepared baking dish.
Top the buns with half the slices of Swiss cheese, followed by half the corned beef, sauerkraut, dressing, and another layer of cheese and corned beef.
Place the top half of the rolls on top to create a sandwich.
In a small bowl, mix together the butter, onion, sesame seeds, poppy seeds, and salt.
Brush evenly on top of the sliders.
Cover the dish with foil and place in oven to bake about 20 minutes.
Remove foil and bake an additional 5 minutes, or until golden brown.