Wash the rice and place in a small saucepan. Cover with cold water to about 2cm above the level of the rice. Bring the water to a boil and simmer until the expanding rice reaches the water surface, then cover and reduce the heat to very low.

Allow the rice to steam for 12 minutes, then remove from the heat and stand, still covered, for a further 5 minutes. Stir the salt and sugar into the rice vinegar. Uncover the rice and transfer to a wide bowl or tray. Add the sesame seeds, then add the vinegar mixture a little at a time while stirring the rice with a spatula using a cutting motion. Allow the rice to cool to room temperature.

Cut the fish into thin slices, if you're doing it yourself rather than using pre-cut fish, and toss in the soy sauce. To serve, place the fish, nori, sliced avocado, cucumber, ginger and wasabi on a large platter. Serve the rice in a bowl. Each person takes a piece of nori, tops it with a spoonful of rice, adds their favourite vegetables and condiments and a bit of fish, then folds it in half like a taco to eat.

Adam's tip Cutting the nori sheets in half allows you to roll big cones of sushi and is more traditional, but I prefer to cut them into quarters. It saves on rolling and uses less rice per piece.