In a medium bowl, mix together the ground beef, chorizo, onion powder, cumin and 2 teaspoons each salt and pepper. Form the mixture into palm-size balls.
Heat a griddle or large skillet over medium-high heat. Place the balls on the griddle and smash with a spatula or the back of a spoon. Cook, flipping once, until cooked through. Divide the Cheddar and queso blanco among the burgers and let melt. Remove the burgers to a plate.
Meanwhile, combine the mayonnaise, ketchup and lime zest and juice in a bowl; mix to blend. Add cumin, salt and pepper to taste.
Toast the slider buns on the griddle. Serve the burgers on the buns, topped with some rosada sauce.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.