Spread 4 bread slices with mayonnaise. Top each with thawed chicken strips, cheese and remaining bread slice; press gently. Spread margarine on both sides of each sandwich.
Spray large nonstick skillet or griddle with nonstick cooking spray. Heat over medium-low heat until hot. Place sandwiches in skillet. Cook 6 to 10 minutes or until golden brown and cheese is melted, turning once. Serve sandwiches with salsa.