Combine the water and sushi rice in a rice cooker and cook according to the settings on the rice cooker. Once cooked, transfer to a large plastic bowl using a wooden spoon and let cool to room temperature (do not cool the rice in the refrigerator).
While the rice cooks, combine the vinegar and monk fruit in a small pot on medium heat. Boil until the monk fruit is dissolved. Pour this mixture over the cooled rice, along with the sea salt.
Use a wooden spoon and mix the rice together, using a cutting motion, until the liquid is absorbed by the rice. Set aside.
To make the sauce, drain the water from the cashews and place into a small food processor (3-cup size is ideal). Add in the soy sauce and sriracha. Use the "chop" setting for 2 minutes. Then, turn to "purée" for about 6 minutes, until the sauce is smooth and creamy. During the purée cycle, you'll need to stop and scrape down the sides several times. Taste and add a pinch of salt, if desired.
To assemble, spread 2 tablespoons of sauce onto a flatbread, covering it completely. Sprinkle 1 teaspoon of sesame seeds on each flatbread. Cut the ends off a sheet of nori so that it fits onto the flatbread. Lay the nori onto the sauce.
With the long end facing toward you, spoon a 1/2 cup of the rice onto the edge and press it out, leaving 1 inch uncovered at each side. I recommend pressing the rice out with slightly damp fingers.
Lay 1/8 of the slices of cucumber onto the rice, followed by 1/4 of sliced avocado. Finally, lay 1 ounce of shrimp in a row.
Tightly fold in the sides of the flatbread and tightly roll it all together, making sure to securely hold the fillings in. Repeat with remaining flatbread.