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 to wash for 30 minutes.
Place the rice in a saucepan and cover with 550ml water. Bring 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.
For the prawns.Run a tooth pick or skewer from top to tail to prevent them curling and blanch in boiling water for 2 or 3 minutes depending on the size. Peel and de vein the prawns, cut from under the belly and open out, be careful not to cut all the way thru.
For the salmon. slice the salmon lengthways into 5 millimeter thin strips, then cut into rectangular pieces 7 centimeters long by 3 centimeters wide.
Making the nigiri. Take a handful of cooked rice, about 2 or 3 tablespoons and roll in your palm into a rectangular cylinder. Put a little of the wasabi on top and then lay the open prawn or salmon over the top. Cut the nori into thin strips, about 5 millimeters wide, run this under and over the nigiri, seal the ends with a little cold water.
«Try making these nigiri with things like omelette, bamboo shoots and wrap them in shiso leaves. »