Coat grill rack with nonstick cooking spray before starting the grill. Place salmon skin side down on the grill. Grill, covered, over medium hot heat for 15 to 20 minutes or until fish flakes easily with a fork. Cool.
For croutons, toss the bread cubes, oil and garlic powder in a bowl. In a nonstick skillet, saute bread cubes for 5 to 6 minutes or until brown, stirring occasionally. Remove from the heat; set aside.
Flake salmon into chunks. In a large bowl, combine romaine and tomatoes. In a small bowl, combine the oil, lemon juice, mayonnaise, sugar, garlic, salt and pepper. Pour over salad and toss to coat. Add the salmon, croutons and Parmesan cheese; toss gently.