Coat a 9 x 13 baking dish with nonstick cooking spray
Cut slider buns in half. Place the bottom halves of slider buns into the baking dish.
Top the buns with a layer of half of the Swiss cheese slices, half of the corned beef, all of the sauerkraut, and all of the Thousand Island Dressing. Top with remaining corned beef, and remaining Swiss cheese. Top off with top halves of slider buns.
In small mixing bowl, combine melted butter, dried minced onion, sesame seeds, poppy seeds, and salt.
Brush butter mixture on top of slider buns.
Cover with aluminum foil and bake for 20 minutes, or until cheese is melted.
Remove aluminum foil and bake for another 5 minutes, or until slider buns are golden brown.