Combine the fish with rice wine, soy sauce and half of the spring onion and ginger in a microwave-safe dish. Microwave for about 3 minutes on medium power. Use a fork to cut the fish into small pieces.
Bring the chicken stock and water to the boil in a stock pot. Add the fish and remaining ginger and bring back to the boil.
Add the cornflour slurry and stir well. Stir in the cucumber and mushrooms and cook for an additional 1-2 minutes.
Season with salt, pepper and sesame oil. Garnish with the remaining spring onions and serve.