Cook the rice according to the package instructions. I cook mine in the instant pot. Check the notes for a link to those instructions.
Mix vinegar, sugar, and salt (if using) in a small bowl. Stir until sugar is mostly dissolved.
Pour vinegar mixture over rice at the end of it's cooking time. Stir to incorporate and fluff the rice a bit.
Boil a pot of water big enough to blanch the tomatoes. Fill a similar sized bowl with ice water.
Score the tomatoes with a sharp, serrated knife in four places from top to bottom.
Drop into boiling water for about a minute.
Remove from water with a slotted spoon and drop into the ice water.
Remove peels from tomatoes and slice in half.
Remove seeds and gooey stuff.
Slice into 1/4" strips and place in a container big enough for them to be in one layer.
Mix tamari (or other sauce) with Sriracha and Aji Nori Furikake (or shred a nori sheet and mix with a tablespoon or so of sesame seeds).
Pour the tamari mix over the tomatoes and set aside. It's best if allowed to marinate for a few hours or overnight.
Place a piece of plastic wrap on top of a bamboo mat. Place a nori sheet on top of the plastic wrap.
Add rice to the nori sheet. With wet fingers spread and press the rice to the left and right edges and leave an inch or two of nori exposed on the top and bottom.
Add a row of filling ingredients across the rice a couple inches up from the bottom.
Carefully, using the plastic wrap to pull, roll the bottom of the nori sheet up and over the filling. Use the bamboo mat (or your hands) to press and make a tight, firm roll. Pull the plastic wrap up and out of the way.
Continue rolling and pulling the plastic wrap out of the way as you roll.
At the end, wet your fingers and run a bit of water along the top edge of the nori. This will form a seal when you complete the roll.
Wrap the finished roll in the plastic wrap and set aside.
Remove the plastic wrap and slice into 1"-1 1/2" slices. Using a serrated bread knife works best.
Place on a plate with a pile of pickled ginger and a little bowl of the sauce and wasabi on the side.