1 Remove any bones from the salmon fillet with tweezers, then pat dry and cut into strips approximately 1 cm wide.
2 Cut the nori sheets in half crosswise, spread with wasabi paste (using your finger) and then cover with rice, leaving about 1/4 of the surface free.
3 Place the strips of salmon on the rice and roll up using a rolling mat. Cut each of the 4 sushi rolls into 6 equal pieces.
5 Wash the rice thoroughly in a sieve under running water until the water runs clear.
6 Put the rice, water and seaweed into a pan and bring to the boil over a high heat. Then cover and cook over a very low heat for about 10 minutes until the rice is swollen. Do not take the lid off the pan during this time! Remove the pan from the heat and leave to stand for 3 to 5 minutes so that the rice can absorb the water.
7 Heat the rice vinegar and mix with the salt and sugar.
8 Transfer the rice to a bowl and remove the seaweed. Draw a chopstick through the rice with a criss-cross action while slowly pouring in the seasoned vinegar. At the same time fan the rice with a fan to ensure that it quickly cools to room temperature and acquires a nice lustre.