2 lbs. fresh Tuna steaks, 1-inch thick good olive oil Kosher salt and freshly ground black pepper grated zest from 2 limes6 tbl. freshly squeezed lime juice (about 3 limes)1 tsp. wasabi power (or more if you like it)2 tsp. soy sauce10 dashes Tabasco sauce2 firm, ripe Hass avocados, large-diced1/2 red onion, thinly sliced1 large ripe tomato, seeded and chopped1/4 cup minced green onions, white and green parts (about 2 onions)21/2 tsp. kosher salt and ground pepper to taste1to 2 tbl. toasted sesame seeds for garnishBrush both sides of the steaks with olive oil and sprinkle generously with salt and pepper.Cook tuna over hot coals for about 2-1/2 minutes on each side or sear in a very hot saute pan.Remove to a plate. The tuna should be seared on the outside and raw inside. Allow to cooland then cut into large bite-size cubes.For the dressing: In a small bowl, whisk together 1/4 cup olive oil, lime zest, lime juice, wasabi powder, soy sauce, Tabasco, salt and pepper.Toss the avocados in the dressing and then arrange the avocados, tuna, tomato, and red onion on individual plates. Drizzle with more dressing and sprinkle with scallions and toasted sesame seeds. Serve at room temp.Can be put onto a bed of fresh greens if desired. I've done it both ways.Note: be sure to coat avocaddos immediately with extra lime juice to keep them from turning brown.