1. Heat grill. In bowl, gently mix ground sirloin, ice water, and salt just to combine. Shape mixture into 4 patties.
2. In bowl, combine mayonnaise ingredients and set aside. Grill burgers 4 minutes per side or until cooked through. Top with cheese for last 1 minute of grilling. Grill buns; spread each with 1 to 2 teaspoons of chipotle mayonnaise. Place burgers in buns; top with avocado slices and salsa.