Wash the rice well and place in a pan with water 2cm above the rice level.
Cover and cook gently for 12 minutes until tender and water is absorbed.
Mix vinegar, sugar, and salt together until dissolved.
Stir the vinegar mixture into the cooked rice and allow to cool completely.
Prepare the cucumber, avocado, and fish by cutting them into batons.
Place a half nori sheet on a rolling mat and spread rice mixture over it, leaving a 1cm margin.
Apply a small amount of wasabi and place a row of fish or vegetables across the center.
Roll the seaweed tightly using the mat and place the join on the bottom.
Trim the ends and cut each roll into six even pieces.
Serve the sushi pieces with pickled ginger and soy dipping sauce.