Using a sharp knife, dice 2 lbs. fresh Ahi tuna into 1/2 inch cubes, place in large bowl and refrigerate.
then peel 1 "finger" of fresh ginger and using a Microplane fine grater, add it to tuna bowl then using a fork fold until incorporated.
Peel and dice one seedless English cucumber then add soy sauce, fold and let it sit for two minutes.
Julienne one scallion on the bias and add it to one cup of ice water, let it sit for five minutes, then strain and place scallions on a paper towel, pat dry.
Pull out the large bowl of diced tuna from the refrigerator and add Ponzu sauce, sesame oil, both black and white sesame seeds and sea salt.
Gently fold all ingredients with a fork.Then place it back in the refrigerator.
Meanwhile julienne one sheet of sushi nori, about 1/2 inch strips and set aside.
Using a sharp knife, fan out one avocado.
Assemble as you wish. Keeping tuna, nori, avocado, and cucumbers separated.
top it all with "Sexy Scallions", lime zest over the tuna and chili flakes over the diced cucumbers.