Season your cooked sushi rice while it's still warm, mix in the sushi vinegar with a spatula, using a slicing motion so we don't smoosh the rice grains too much;
In a large bowl, mash the beans until mostly smooth but with leave some texture, add in the grated beet and carrot, chopped scallion, miso, mustard, lemon juice, fold to mix in evenly, taste and season with salt and pepper to your liking;
Once you have everything ready, thinly slice your avocado, make cutting avocado the last step you do to minimize oxidization;
Line glass Tupperware or bake pan with cling wrap or parchment paper, fan out the avocado and lay the slices flat on the bottom;
Then add the bean salad, and then rice, press to flatten;
Cover and refrigerate for 30 minutes;
Flip the pan over, cut into bite size squares, serve with crispy seaweed, enjoy!