1. Make two shallow cross-shaped cuts at the base of each tomato.
2. Bring a pot with plenty of water to high heat.
3. When the water starts to boil, add the tomatoes and let them cook for 1 minute.
4. Quickly transfer the tomatoes to a container with ice water.
5. Peel the tomatoes and remove the seeds.
6. Cut the tomatoes into small squares.
7. In a container, mix the soy sauce, sesame oil, rice vinegar, and small pieces of nori seaweed.
8. Prepare the sushi rice. To do this, wash the rice repeatedly to remove as much starch as possible. After washing, soak the rice in cold water for 10 minutes.
9. Bring a saucepan to high heat, add 1 cup of water and the rice.
10. When the rice starts to boil, reduce to low heat and cook for about 5 minutes.
11. Remove the rice from the heat and let it rest at room temperature.
12. Mix the rice vinegar with a tablespoon of sugar and a little salt. Pour this dressing over the rice once it's cold.
13. Stir with folding movements.
14. On a sushi mat, spread out a sheet of nori seaweed, put some rice on top and the marinated tomato.
15. Carefully form the sushi roll, making sure the filling doesn't spill out.
16. Cut the roll into slices about 1.5 cm thick.
17. Accompany the dish with vegan mayonnaise.