Rinse rice in a colander until the water is no longer cloudy. Combine rice and water into a rice cooker and cook, or follow package directions to cook the rice. (For an instant pot, add 4 cups sushi rice and 4 cups water. Cook on the rice setting for 12 minutes, then natural release for 10 minutes).
While the rice is cooking, make the vegan crab. Put the hears of palm, bell pepper, and nori sheet in the food processor and pulse until chopped. transfer to a bowl and add mayo, white pepper, and stevia.
Next make the rice su by adding the turbinado sugar, rice vinegar and salt to a sauce pan and heat on medium heat. Stir until all the sugar and salt is dissolved. When the rice is finished, combine the rice and rice su in a large bowl and toss with a rice paddle. It is best to start out with a slicing motion to mix the rice without smashing it. Then mix gently, as you normally would. Put the rice in the fridge for about an hour to allow it to cool. Remember to put all other ingredient in the refrigerator while you wait.
Next, cover a bamboo mat with a layer of plastic wrap. Have a small bowl of water and a dish towel near by to wet and wipe your hands during this process.
Slice avocado and cut cucumber into long slices, and cut out the seeds.
Now Roll your sushi!
Lay down a sheet of nori, and cover with a thin layer of rice. To do this, wet your free hand and alternate using the paddle and free hand to flatten down the layer of rice. Leave a about an inch strip of nori without an any rice on the side furthest away from you.
Add sliced avocado, cucumber, and vegan crab in a row on the side of the nori closest to you. Dip fingers in water and coat the exposed strip of nori.
Roll your sushi by picking up the edge of the mat, roll the edge of the nori over the toppings and squeeze hands in a fist, as if gripping the beginning of the roll with toppings inside. Gently release the mat and continue to roll the sushi. When you get to the end, firmly press into a roll shape for a couple seconds. Transfer to a cutting board and slice with a very sharp knife.