To make the seasoning, place the vinegar, sugar and salt in a saucepan, bring to a boil, reduce to a simmer and stir until the ingredients are dissolved.
Place the rice in a colander and wash thoroughly under cold running water. Leave the rice to soak in a saucepan with the 550ml of water for 30 minutes.
Bring the rice to the boil and then reduce to a low simmer. Cover with a lid and cook without stirring for 10 minutes. Remove from the heat and set aside, covered, for another 10 minutes.
Place the rice in a large bowl. Pour the vinegar seasoning over the rice and mix the seasoning through the rice. Continue turning the rice for a couple of minutes. Cover with a damp cloth and leave to cool to room temperature before serving.
Cut the nori sheet into 4 portions. Place a sheet in your hand and place a small ball of vinegared rice in the centre of the nori. Add a slice of avocado and some of the crab. Sprinkle with toasted sesame seeds and add a dash of wasabi. Roll into a cone shape. Repeat to create the remaining portions.
«This recipe can be varied to include shrimps or scallops rather than crab.»