Clean the bloodline and any extra sinew from the hamachi fillet. Set aside.
In a bowl, whisk together the sriracha and sesame oil. Stir in the fish sauce. Taste and check for heat; if too spicy, add fish sauce and sesame oil in small increments.
Remove half of the sriracha mixture to another bowl and mix in sake and cilantro. Add the hamachi, cover and let marinate in the refrigerator for at least 3 or 4 hours and up to 1 day.
Using a mortar and pestle or spice grinder, grind the sesame seeds and sea salt into a uniform powder. Set aside.
When the hamachi has cured, cut it into clean 1/8-inch slices and arrange on 4 to 6 small plates. Drizzle some of the reserved sriracha mixture over the fish and sprinkle the ground sesame seed mixture around the plate.
Garnish with pickled ginger and chives. Serve cold.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Michael Perrin, Executive Chef and Owner, 11 Maple Street, Jensen Beach, FA