1 Wash the rice thoroughly in a sieve under running water until the water runs clear. Put the rice, water and seaweed into a pan and bring to the boil over a high heat. Then cover and cook over a very low heat for about 10 minutes until the rice is swollen. Do not take the lid off the pan during this time! Remove the pan from the heat and leave to stand for 3 to 5 minutes so that the rice can absorb the water.
2 Heat the rice vinegar and mix with the salt and sugar.
3 Transfer the rice to a bowl and remove the seaweed. Criss-cross a chopstick through the rice and at the same time slowly pour in the seasoned vinegar. Then immediately fan the rice with a fan to ensure that it quickly cools to room temperature and acquires a nice lustre.
4 Roll out half of the rice on a moistened work surface to a thickness of approximately 1.5 cm. Moisten a heart-shaped biscuit cutter with water and cut out 10 hearts. Cut 10 hearts out of the salmon also. Brush one side with a little wasabi paste and lay on top of the rice hearts.
5 Cut the nori sheet in half crosswise and lay each halved nori sheet on a bamboo rolling mat, smooth side down. Cover with a layer of prepared rice (at room temperature) approximately 1 cm thick, but don't press the rice down too firmly. Leave a small border free on the long edges. Using your finger tip spread a little wasabi paste lengthwise on the rice. Roll up using the mat and form the rolls into heart shapes.
6 Cut each roll into 5 equal pieces.