In a small bowl, combine the mayonnaise, chili paste, lemon juice, bonito flakes, fish roe, and a pinch of sea salt. Put the tuna cubes in a mixing bowl and gradually fold in the mayonnaise mixture a little at a time to coat the fish. There will be some left over. Cut the nori sheets in half. Place half a sheet, shiny side down, in the palm of your hand. Dampen your fingers and spread a thin, even layer of sushi rice over half the sheet covering your palm side. Spoon a generous tablespoon of the spicy tuna down the center of the rice. Now, read this next part a few times before you attempt itâ€”itâ€™s a little tricky: To form a cone, start with the inner corner that is closest to the palm of your hand. Fold it in toward the center of the paper, covering the rice. Continue to roll until it forms a cone; then dab the far edge with a little water to seal the cone. Top it off with a little more of the spicy tuna so it looks full, and garnish with chopped green onion.
Edited: October 9th, 2009