Ingredients      Serves 4      600 grs fresh tuna, in four 150-gr portions      1 ½ cup soy sauce      ½ cup dry sherry      2 green onions      4 cylindrical moulds, 15-cm high and 6 cm in      diameter      2 avocados, chopped      160 grs cream cheese      Grated lemon zest      4 tbl sesame seeds      10 grs fresh ginger, minced      1 ½ cup balsamic vinegar      1 tbl sugar      salt      black pepper      chilli pepper or paprika for garnish         Directions:      Blend the soy sauce, sherry, and green onion. Add the fish portions and toss lightly to coat. Place in the refrigerator to marinate.      In a separate bowl, mix the avocado, the parmesan cheese, and lemon zest; season to taste and distribute evenly among the 4      moulds. Sprinkle with sesame seeds and top with arugula leaves without crushing them. Set moulds aside.      Place the ginger, bal samic vinegar, the remaining soy sauce, and the sugar in a saucepan over medium heat. Stir well and re-      duce by half. Remove the pan from the heat and allow to cool.      Just before serving, add the olive oil and beat briskly. Add salt and pepper to taste. Re move the tuna from the marinade. Pour      olive oil into a frying pan and bring to high heat. Add the tuna and seal quickly on each side, adding salt and pepper at the end.      Presentation:     Place the timbale at one edge of the plate; remove the mould and drizzle with the dressing, allowing some to dribble attractively     across the plate. Place the tuna at the opposite edge of the plate. Sprinkle with chilli powder and serve.