Since the sushi will be rolled uramaki style (inside out / California style), wrap your bamboo sushi mat with Glad / Cling wrap (“Saran” or “Plastic wrap in the USA) to prevent the sushi rice from sticking to the mat. I will post a detailed video on how to do this soon! NOTE 2 for a written explanation.
Take your nori seaweed, and cut 3 rows down from the top (horizontally, see photos in the blog for reference). Dip your fingers in water to prevent the rice from sticking to your hands- and take enough rice to cover the seaweed in a thin, even layer. Flip it over so that the rice is now facing down onto the plastic wrap.
Place two long sticks of cucumber in the center of the roll, followed by the tempura prawn, tails should be facing outside of the roll. Add some sliced avocado to the roll if using, as well as a thin layer of Kewpie Mayo. (Optional: smear a thin layer of wasabi to the center of the seaweed for an additional kick before adding the other elements).
With a firm grip, tightly begin rolling the sushi away from you, ensuring the roll is compressed sufficiently whilst you roll. Once you get to the end of the roll, give it a tight squeeze from the center outwards towards the end, ensuring the roll is nice and tight.
If you are garnishing the roll with sliced avocado: take the avocado and peel the skin off the back. Finely slice the avocado horizontally, and gently flatten, then place it over the roll of sushi and spread it so that it covers the entire roll. Then, using the same technique, but lightly less pressure, roll the sushi in the plastic-covered mat another time to mould the avocado around the sushi roll.
Using a sharpened or serrated knife, slice your sushi rolls once through the center (you may need to wet the knife inbetween slices), and then slice in the center of both halves, and through the center of each sliced quarter – you should have 8 nice slices of sushi per roll.
Garnish with a drizzle of Kewpie mayo, teriyaki sauce and any other toppings you like! I like to do sliced green chilli with sriracha for extra spice, you can use capelin fish roe – or just super-finely grated carrot for presentation!