For the kingfish, whisk together miso paste and mirin. Coat the fish in the paste and marinade for 30-60 minutes.
Meanwhile, make the salad. Mix together daikon, cucumber, radishes, and spring onions. In a separate small bowl or jug, mix together vinegar, light soy and mirin. Taste for balance of flavours. Adjust to suit your personal taste. Keep the vegetables and dressing separate until the fish is cooked, or the salad will lose it’s crunch.
Turn you grill up to its highest heat. Line a tray with a piece of baking paper and place fish skin side down. Grill for 5 minutes, then turn so the skin side is up and grill until the skin is crisp and the fish is cooked through.