Beat the egg with 1 cup of water. Mix in portions of the sifted flour at regular intervals. Season with salt and pepper. Whisk as minimally as possible to avoid over-incorporating air.
Heat enough oil in a pot that it can cover the avocado until it is very hot; dip avocado slices into the batter, and lay into the oil away from you. Fry until brown, about 1 minute a side. Use a slotted spoon to remove tempura from oil, and place onto a plate lined with paper towels; use them to absorb the oil.
On a large working surface, set aside a bowl of cold water. Dip your hands in cold water and grab 1 cup of the sushi rice, and disperse evenly onto a sheet of nori. Press firmly downward to make sure the rice sticks. Top with sesame seeds and bonito flakes. Flip over, top with 1/2 the avocado tempura, crab salad, Asian slaw, cucumber, and sriracha mayo. Use your hands and roll the nori into a burrito shape; use your fingers to make sure that the filling doesn’t slide out when you roll the seaweed and rice. Place onto a piece of parchment paper roll to wrap. Cut in half using a serrated knife and serve.