Filling: Soak the beans in water overnight.
Drain and put in a saucepan.
Add enough water to cover, add the salt and soy sauce and cook until the beans are soft, 1-2 hours.
Mash the beans with a potato masher and mix in the garlic and ginger.
Rice: Rinse the rice until the water is clear.
Drain the rice for 60 minutes to ensure it's dry then put it in a saucepan with a tight-fitting lid.
Add the water, bring the rice to the boil and simmer for five minutes.
Reduce the heat and steam for 12-15 minutes.
Remove the saucepan from the heat, remove the lid and cover the saucepan with a tea towel.
Leave to stand for 15 minutes.
While the rice is cooking heat the rice vinegar, mirin, sugar and salt over low heat, stirring until the sugar has dissolved.
Remove from the heat and leave to cool.
Evenly spread the rice on the bottom of a wooden or plastic dish.
Slowly add the rice vinegar mixture, stirring the rice continuously with a spatula.
Cool the rice with a fan or book until it reaches room temperature.
Cover the rice with
a tea towel until needed.
Sushi rolls: Put a nori sheet shiny side facing down on a bamboo mat.
your hands with the vinegar water and carefully spread 180 ml of the rice over
the nori, leaving a 12 mm edge at the far end of the sheet to seal the roll.
Spread the bean filling over the rice and lay strips of green pepper diagonally in the centre of the sheet.
Moisten the strip of nori at the top with rice vinegar and, using the bamboo mat to guide you, roll up the sheet firmly.
Repeat with the remaining nori sheets and ingredients.
Leave the rolls to rest for a few minutes before slicing with a knife dipped in water.
Serve the rolls with teriyaki sauce and wasabi (Japanese green mustard).