Combine first 6 ingredients in a medium bowl; stir well, and set aside.
Prepare grill or broiler. Place chicken strips on grill rack or broiler pan coated with cooking spray, and cook 5 minutes on each side or until chicken is done.
Combine buttermilk and next 6 ingredients (buttermilk through garlic) in a large bowl; stir well. Add romaine salad, tomatoes, and croutons; toss gently to coat. Spoon salad mixture onto each of 4 plates, and top with chicken strips.
Note: Substitute 12 cups sliced romaine lettuce for 1 (10-ounce) package ready-to-eat romaine salad, if desired.