Prepare the sushi rice according to package instructions (I use a rice cooker - fool proof).
Prepare your veggies while the rice is cooking.
Once the rice is done put it in a bowl and season to taste with rice vinegar and sugar - the mixture should be pleasantly sweet and sour. Spread up the edges of the bowl to cool for a couple of minutes.
Lay down a nori sheet on a rolling mat. Using a spoon dipped in water spread the rice (min. 1/2 in / 1.5 cm thick) on the nori leaving a strip of about 2 in / 5cm at the far side of the sheet facing away from you.
Use a teaspoon to spread some plum sauce down the middle of the rice. Top with 1-2 slices of cucumber, carrots, avocado and green onion each depending on size of the veggies you cut (they need to spread all along the middle of the rice from end to end).
Using your mat roll up the nori pressing down with your hands as you roll to keep the roll firm.
Set the rolls on a plate with the bare strip of nori facing down. The moisture from the rice will seal the rolls. Let sit to firm up.
Using a sharp knife cut the ends of the rolls and eat immediately ; )
Cut the rest of the rolls into neat bite sized pieces and serve with the wasabi and pickled ginger and soy sauce for dipping - you may want to let your guests decide on how much wasabi to use, especially if they are French : ).