Preheat oven 350°. Slightly spray 13x9-inch baking dish with nonstick spray. Slice slider buns in half. Place bottom buns in prepared baking dish; set aside.

Combine skinless brats in a bowl. Shape brats into 9 (2-inch each) patties. Heat a large nonstick skillet over medium heat; spray with nonstick cooking spray. Cook patties 6 minutes, flipping once halfway through, or until internal temperature reaches 165°.

Meanwhile, combine French onion dip, mayonnaise, and sauerkraut in a medium bowl. Spread bun tops with French onion mixture.

Layer bottom buns with slider patty, cheese, and top bun. Bake 6 minutes or until cheese is melted and sliders are heated through.