Place each square of nori flat onto a sushi rolling mat. (Sushi rolling mats are available from Asian supermarkets and larger supermarkets.)
Place a layer of cooled sushi rice onto the seaweed wrap and gently press flat. (NB: don't add too much rice or you will end up with very fat sushi rolls.)
Place a dab of wasabi paste along the rice, according to taste. Wasabi is quite strong, so be sparing!
Place a thin slice of salmon onto the rice.
Spread the strips of cucumber onto the salmon and add a sprinkling of spring onion.
Carefully roll the sushi up into a sausage shape and slice it into 3cm/1in long pieces, trimming the ends.
Serve with bowls of soy sauce and extra wasabi.
