Hiro Blue

I believe the dish you are referring to is known as "Hiro's Blue Fin Tuna" or "Hiro's Blue Fin Tuna Auction," which can be found in high-end sushi restaurants in the United States. The name "Hiro" refers to the chef, Hiroaki Nakano, who was the first sushi chef to win a bid at the famous Tsukiji fish market in Tokyo, Japan.

The dish features a slice of premium bluefin tuna, usually from the fish's prized bluefin tuna's belly, served as sashimi or nigiri. The tuna is often served with soy sauce, wasabi, and pickled ginger. The high quality of the tuna is the main draw of the dish, with the fish typically being sourced from the Tsukiji fish market or similar markets in the U.S.

The serving size is usually small, and the dish is quite expensive due to the rarity and high demand for bluefin tuna. If you get a chance to try this dish, you will appreciate the delicate texture and rich, buttery flavor of the tuna, which is considered to be one of the finest sushi experiences.