To make the marinade, mix the olive oil, soy sauce, garlic, ginger, lemon juice and wasabi in a shallow, non-metallic dish. Add the tofu, stir well and chill until required.
To make the salad, put the lettuce, tomato, spring onion, garlic, avocado, fennel and alfalfa sprouts in a bowl. Add the sunflower seeds and lime juice. Season with salt and pepper and toss well. Cover and chill until required.
When ready to serve, heat a heavy-based frying pan and add a small amount of oil. Fry the tofu strips until golden brown on both sides. Peel, stone and slice the avocado and add to the salad with the oil. Toss and top with tofu. Serve immediately with the alfalfa salad.