Preheat a grill to medium-high.
In a large bowl, combine the ground turkey with the minced red onion, green onion, chile, egg whites, Southwest Essence, cumin, and Worcestershire. Mix gently but thoroughly. Divide the mixture into 12 equal portions, and using your hands, shape them into 12 small burgers, each about 3 1⁄2 inches wide.
Place the burgers on the grill and cook until the turkey is just done and an instant-read thermometer inserted into the center registers 165°F, about 3 minutes per side.
Serve the burgers on the mini buns, topped with the cheese, lettuce, tomato, sliced red onion, and avocado. Garnish with mayonnaise, mustard, and ketchup to your liking.
Yield: 12 sliders, 6 servings