Prepare the rice in accordance with package directions.
Wash the roma tomates and cut a shallow cross hatch in the top of each. Briefly blanch the tomatoes in boiling water for 1-3 minutes, until the skins start to peel. Remove from boiling water and place in an ice bath.
While the tomatoes are cooling, combine the tamari, garlic, ginger, nori and sriracha in a mixing bowl.
Peel the skin from the tomatoes, then slice each tomato into quarters lengthwise. With a sharp knife, remove the seeds from piece and slice into small pieces.
Marinate the seedless tomato pieces in the tamari marinade.
Mash the avocado.
Combine the rice vinegar, sugar and salt in a small pot. Bring to a boil and whisk until the salt and sugar are dissolved. Add the solution to the cooked rice and allow the rice to cool.
Strain the tamari marinade from the tomatoes. The garlic, ginger and nori will remain with the tomatoes.
Using a food ring, prepare the “tuna” tower by packing the bottom third with the cooled, seasoned rice. Add a layer of avocado. Add a second layer of rice.
Gently remove the food ring and top the tower with the “tuna.” Sprinkle with sesame seeds, crushed pistachios and microgreens. Serve with tamari and wasabi paste. See recipe notes.