Put the sushi rice in a saucepan with 220ml water, then
add a small stick of kombu, if using. Bring to the boil
and stir, then continue to simmer until the rice becomes
porridge-like; you may need to add more water.
Preheat your oven to the lowest setting. Pour the rice
mixture on to a baking tray then spread evenly and dry
out for 3-4 hours, or for as long as possible. Once the rice
has dried, it will look like a translucent plastic sheet.
Pour the rapeseed oil into a saucepan and heat to
200C/400F, or until almost smoking. Break small pieces
from the rice sheet and drop into the oil; the rice will
immediately fizz then roughly triple in size, so don't fry
too much at once. Drain on kitchen paper.
To make the dip, put all the ingredients into a large mixing
bowl then mash together, leaving a few larger pieces of
avocado for texture, then serve with the rice crackers.