Poke - pronounced "po-kay" - is a Hawaiian dish that almost certainly has its influences from the Japanese immigrants who settled in the state. The seasonings vary from cook to cook - you can make it spicy or mild, use other types of fish or shellfish, or different vegetables (I like to add onion, cucumber, tomato and pickled seaweed). The shiso leaves or nori sheets are optional, but I like to spoon the mixture on to a leaf, wrap it up and eat it. You can also eat the poke with rice (white or brown) or another type of cooked grain.
Because it's eaten raw, it's essential that the fish is of top quality. Buy it from a supermarket that keeps its seafood on ice. Ask the fishmonger for recommendations on which of their products are suitable for eating raw.
Cut the tuna into 1cm (7/16 inch) cubes and put them in a bowl.
In a small bowl, mix the sriracha sauce with the soy sauce, sesame oil and honey. Dip a piece of the fish into the mixture and taste for seasonings, adjusting as needed. Pour the sauce over the tuna and mix gently.
Halve the avocado and remove the pit. Cut the flesh into cubes then use a large spoon to scoop them out of the shell.
Gently mix the avocado with the tuna, sprinkle with sesame seeds then mix again. Pile the poke onto a plate then garnish with the radish sprouts and spring onion. Serve with the optional ingredients.