Preheat oven to 375º F. Lightly coat a baking sheet with nonstick cooking spray and set aside.
In a mixing bowl, use your hands to combine salmon, breadcrumbs, red onion, mustard, mayo, lemon juice, cayenne pepper, chili powder, salt, and pepper.
Shape mixture into 6 equally sized burger patties, about ¾ cup per patty. Evenly space patties on baking sheet. Lightly spray the tops of the burgers with nonstick cooking spray. Bake for 20 minutes or until golden brown.
Meanwhile, make the Chili Lime Sauce by whisking mayo, chili powder and lime juice in a small bowl. Set aside.
When burgers are cooked through, remove from oven. Serve burgers on buns, topped with 1 tablespoon Chili Lime Sauce, ⅓ cup of spring mix and a lime wedge.