Place under a cold running tap and rinse until the water runs clear, then drain really well and place in a saucepan.
Pour over 350ml water. Bring to the boil and cook about for 5 mins until most of the liquid has boiled away and small holes appear in the rice. Turn the heat down as low as it will go. Cover the pan with a really tight-fitting lid or tin foil and leave for 10 mins. Then turn off the heat and leave for another 10 mins.
Heat the rice wine vinegar, sugar and a pinch of salt together in the microwave for about 30 secs until the sugar dissolves. Tip the cooked rice into a large bowl.
Pour over the warm rice wine mixture and stir through, then leave the rice to cool down.
Line a 20 x 20cm baking tin or similar-size dish with a double layer of cling film.
Spread the sushi rice over the bottom of the tin (the mixture will be a little sticky, so you may have to wet your hands to do this). Then cover the rice completely with smoked salmon slices. Fold the cling film over the salmon to cover pressing down well with your hands to mould everything together. You can chill the sushi in the fridge until ready to use, but try not to chill it for longer than 3 hrs or the rice will harden.
To serve, dip a sharp knife into a little hot water to stop the rice from sticking, then cut into 16 rectangles.
