Start by preparing and cooking the rice first.
I always do this in advance. This is how this needs to be done.
Wash rice thoroughly by placing it in a sieve and running cold water through for about 2 minutes. Leave on the sieve to rest for min 20 min.
While the rice rests prepare the tuna mix. Take a mixing bowl, put the tinned fish and the avocado in and mix with a fork until the fish becomes really small flakes.
Put the rice in a pot, pour water over and cover with lid. Cook on medium heat for 12-13 min. Keep an eye on it and when water starts boiling turn the heat down to low and cook until the 12-13 min are up.
When the time is up turn heat off and pour all over it the 120 ml sushi vinegar. Take the rice out in a bigger dish where you can mix it well and also it allows it to cool a lot quicker. Allow it to rest and cook for 15 min or so.
Chop all the needed ingredients, the cucumber, pepper, spring onion, avocado and the surimi.
Prepare a springform dish by either slightly oiling the edges or lining it with the seaweed sheets. Start by layering 1/4 of the rice using a metal or wooden tablespoon. Apply some pressure on to the rice and press it down all uniformly until you have the same thickness all throughout.
Immediately over the rice sprinkle most of your chopped ingredients. Depending on the number of rice layers you choose to have you can simply choose how to distribute the ingredients between the layers. Place another rice layer and then spread the tuna mix equally so that this covers the whole surface.
Once the last rice layer has been placed press down as usual and cover with a cling film. Place a spring form bottom of a slightly small form over the cling film it and place some heavy bottles or jars over to press the whole cake and firming it up to make it easier to cut later when serving it.
Finish by taking it out of the form, placing it on a plate and decorating your sushi 'cake' with a few more of your chosen ingredients and some fish roe.
Absolutely unbelievable sushi with a lot less work. Enjoy it folks and let me know where your creativity has taken you making this amazing homemade sushi cake.