Bone snapper and slice the fish fillets into thin sashimi slices and arrange flat on a plate. Puree sea urchin with a hand blender or a small bar blender.
With a tablespoon, pour the following liquids around and over the sashimi; ginger juice, soy sauce, yuzu juice, lemon juice, truffle oil, sea urchin, and spicy sesame oil. Garnish with fresh truffles, Japanese herbs, and droplets of scallion oil.
Quickly blanch green onions in hot water and shock immediately in ice water. Squeeze out the water from the green onion and place in blender with the olive oil. Add the ginger juice, season with salt, and blend. Strain through a fine sieve.