1. Wash the rice very well in cold water, gently rubbing it with your hands, until the water runs clear. Drain it and place it in the rice cooker with the water. Close the lid and let it cook until it absorbs all the water and becomes soft but not mushy. Once cooking is finished, leave it covered for about ten minutes to 'rest'. Alternatively, place it in a saucepan with the water.
2. Once it comes to a boil, reduce the heat to the minimum, cover, and let it simmer until all the water is absorbed. Do not stir at all. When it's ready, remove it from the heat and leave it covered for ten minutes.
In a small saucepan, gently heat the rice vinegar with the sugar and salt over low heat until they completely dissolve. You don't want it to boil. Transfer the warm rice to a wide bowl. Drizzle the seasoning evenly and gently mix with a wooden spoon or spatula, using cutting motions so the rice doesn't break down. Let it cool to room temperature, covered with a damp towel.
3. Lay out the bamboo mat and cover it well with plastic wrap so the rice doesn't stick and you can roll easily. Cut the nori sheets in half and place them on the bamboo mat.
Dip your hands in a little water so the rice doesn't stick and spread a thin layer of rice on the shiny side of the nori, pressing gently without crushing it. Don't overfill; you want the rice layer to be even.
4. In the center, add the fillings of your choice: cucumber, pepper, or avocado, along with fried shrimp, crab sticks, or smoked salmon. Roll tightly using the bamboo mat, pressing gently to shape the roll correctly.
Once closed, place thin slices of fruit, such as mango or kiwi, on top and press gently again with the bamboo mat to secure them onto the roll. Dip your knife in water and cut the sushi.
5. For crispy sushi, prepare the tempura by dissolving the mix with cold water until it forms a thin batter. Dip the roll first in the tempura batter, then in the panko, and fry it in hot sunflower oil until golden brown and crispy. Remove it onto absorbent paper.
Let the rolls 'set' for a little while and cut them by dipping the knife in water.
Serve the sushi, accompanied by soy sauce and wasabi.
