Cook the fish on in a pan with high heat for a minute. On each side. Make sure that surfaces should be seared and inside raw. Immediately plunge into iced water. Drain and hand dry with paper tower towel and cut into thick slices of 1/7 inches.
Make the dressing by mixing Wasabi paste, Lemon juice and soy sauce in small bowl and set aside.
Keep the lettuce in iced water before serving to get the crispy texture.
Arrange the salad leaves and enoki mushrooms in the centre of the salad plate, layered the sliced fish on it and top it with the dressing and serve.