Brush the tuna steaks with olive oil, and sprinkle with salt and pepper. Place the tuna steaks in a very hot saute pan and cook for only 1 minute on each side. Set aside on a platter.
Meanwhile, in a small bowl, combine the olive oil, salt, pepper, lime zest, wasabi, lime juice, soy sauce and hot sauce. Add the avocados to the vinaigrette.
Cut the tuna in chunks and place it in a large bowl. Add the scallions and red onion and mix well. Pour the vinaigrette mixture over the tuna and carefully mix.
