1. For aioli, in a small bowl combine mayonnaise, lemon peel and juice, dill, and garlic. Mix well, cover, and refrigerate until crab cakes are ready.
2. For crab cakes, in a large bowl, combine mayonnaise, mustard, egg, cayenne, 1 cup bread crumbs, celery, red bell pepper, and green onion; mix well. Gently stir in crabmeat.
3. Place remaining 2 cups bread crumbs in a shallow dish. Shape crab into small cakes (about 1 1/2-in. diameter); coat with bread crumbs, pressing gently to adhere.
4. Place apart in two oiled 12- by- 17-in. rimmed baking pans. Bake in a 500° oven for 7 minutes, switch pan positions, and continue baking until golden brown, about 7 minutes longer. Serve hot with aioli.