1
Rinse the rice thoroughly until the water runs almost clear, then drain well. Transfer to a rice cooker pot and add the measured water and kombu. Without stirring, let soak for 20 to 30 minutes, then begin cooking using the sushi setting if available.
2
Combine rice vinegar, sugar, and salt in a microwave-safe bowl. Whisk together, then microwave for one minute until the sugar dissolves. Stir again and set aside to cool.
3
Once the rice is cooked, remove the kombu and transfer the rice to a wooden sushi tub or large salad bowl. Spread the rice evenly to cool faster, then pour the sushi vinegar over the hot rice.
4
Using a rice paddle, gently slice the rice at a 45-degree angle to fold in the vinegar and separate the grains, flipping gently between slices. Do not stir as this breaks the grains. While slicing, use a paddle fan to cool the rice rapidly, which also removes excess moisture and creates shine.
5
Peel the cucumber in a striped pattern, trim the ends, and cut into thin sticks. Slice the takuan into thin sticks in the same manner.
6
If the sashimi comes as a block, cut it into long strips, or ask the fishmonger to cut it into strips suitable for hand rolls. Shred the imitation crab into thin strips. If using natto, defrost it overnight in the refrigerator and mix with the sauce before serving.
7
Arrange shiso leaves on a platter, place ikura in a small bowl, and arrange various sashimi by type into separate piles. Prepare a second plate with vegetable fillings such as cucumber, takuan, shiso leaves, and daikon sprouts.
8
Season canned tuna with mayonnaise and soy sauce. Cut nori sheets in half or quarters according to preference.
9
Set the table with a medium plate and small soy sauce dish for each guest. Bring the sushi rice, sashimi platter, vegetable fillings, and nori sheets to the table. Optional sides such as gyoza and karaage can also be served.
10
To make traditional cone-shaped temaki, place a half sheet of nori with the rough side up. Spread a small amount of rice on the left side, add your choice of fillings such as cucumber, sprouts, salmon, and ikura, then roll into a cone shape.
11
For a taco-style variation, use a quarter sheet of nori. Experiment with different combinations such as takuan with chutoro or squid with tobiko. For fatty sashimi like salmon belly and chutoro, sear the fish lightly before wrapping to add charred flavor.