Preparation / Directions:
* A green Asian horse-radish available at Asian Markets, well-stocked grocery stores and some health food markets.
(Note: In place of wasabi, you could use an equal amount of powdered dry mustard)
In a shallow glass dish, combine 1 T of the soy sauce and 1 t of the oil. Add the tuna and coat well. Refrigerate for about 15 minutes, turning fish twice.
Light grill or preheat grill. In small bowl, mix wasabi powder with 4 t of hot water. Cover and set aside for 5 minutes.
In another bowl, stir 2 T of warm water into the tahini. Stir in the wasabi paste, vinegar, mustard, sugar, garlic and the remaining 2 t soy sauce and 4 t oil. Season with salt and pepper.
Season the tuna with salt and pepper; grill until crusty on the outside and rare within, about 4 minutes per side.
Transfer the fish to a plate to rest for a few minutes, then slice it against the grain 1/3 inch thick.
In large bowl, toss the alfalfa sprouts with the enoki mushrooms and all but 2 T of the dressing. Scatter spinach leaves on 4 large plates and arrange tuna on top. Drizzle on the remaining 2 T dressing. Mound the sprout salad on the tuna, scatter the pickled ginger on top and serve.
Reprinted from Food and Wine Magazine, July 1996.