Preheat oven to 450 degrees F. Coat a baking pan with nonstick cooking spray; set aside. Shred peel and juice half of the lime; cut remaining lime into wedges. Stir together juice, peel, wasabi paste, and mayonnaise. Transfer 1 tablespoon of the wasabi mayonnaise to bowl. Cover and refrigerate remaining wasabi mayonnaise.
Sprinkle fish with salt. Place fish in baking pan. Coat with 1 tablespoon of the wasabi mayonnaise, then 3/4 cup panko. Drizzle with 1 tablespoon melted butter. Bake on middle oven rack for 20 minutes or until fish flakes easily with a fork.
Remove fish from pan. Toss beans with the panko that remains in baking pan. Sprinkle with remaining 1/4 cup panko. Serve with remaining wasabi mayonnaise and lime wedges.