To prepare dressing, combine first 7 ingredients in a bowl; stir well with a whisk.
Prepare grill or broiler.
Sprinkle both sides of steak with salt and pepper. Place steak on a grill rack or broiler pan coated with cooking spray, and cook 6 minutes on each side or until desired degree of doneness. Let stand 10 minutes. Cut steak diagonally across grain into thin slices; cut each slice into 2-inch pieces.
Combine steak, lettuce, and remaining ingredients in a large bowl; add dressing, tossing to coat.