To make the tartar sauce, combine first 5 ingredients in a small bowl. Cover and chill 3 hours.
Sprinkle grouper with lemon pepper. Grill fillets, covered with grill lid, over medium-high heat (350° to 400°) 4 minutes on each side or until fish flakes with a fork. Place each fillet on a Kaiser roll. Top with Chipotle Tartar Sauce, tomato, onion, and cabbage.