For the Ponzu, you'll want to start out by bringing the soy sauce, chicken stock, olive oil, and lemon juice to a simmer in a saucepan. Combine wasabi and water to make a paste, then add it to the Ponzu.

Heat a small amount of olive oil in a saute pan. When the oil is about to smoke, add your tuna and sear briefly on all sides. I like my tuna "blue" which requires about 6 seconds per side. Your time will vary depending on the size of the fish; just use your best judgement.

After the fish has rested, slice the tuna much like Tataki. I serve my tuna with Jasmine rice, ginger, and lemon zest, and the Ponzu on the side for dipping.