Put the shiitake mushrooms in a bowl and add 1 1/2 cups of boiling water. Let these rehydrate for 30 minutes. Squeeze out the extra liquid from the mushrooms, (reserving the soaking liquid for later) remove and discard the stems, and then chop into thin squares.
Put the koyadofu in a bowl of room temperature water for 30 minutes. Squeeze out the extra water, and then slice it into small thin squares.
While you are waiting for the dried ingredients to rehydrate, roast the bell peppers using the instructions here. After roasting and peeling, slice them into 2-inch long strips. To make the seasoning combine 1 teaspoon of sugar with 1/4 teaspoon of salt and sprinkle on the bell peppers, tossing to coat evenly.
To blanch the snap peas, bring a pot of water to a boil. Prepare a large bowl of icewater and trim the fibers off the top and sides of the peas. When the water comes to a boil, add the snap peas and blanch for 30 seconds. Drain and immediately dunk them in the ice water. Drain the snap peas and slice into thin long strip at an angle.
Prepare a bowl of water with a teaspoon of lemon juice or vinegar in it. Peel the lotus root and chop into 1/4-inch pieces, putting them in the acidified water to keep them from changing color. Drain them before sautéing with the other vegetables.
Next, start on the sushi rice.
Once the shiitakes and koyadofu are rehydrated and prepared, add the oil to a frying pan over medium-high heat. Sauté the carrots for 1 minute.
Add the shiitake mushrooms, koyadofu, lotus root, and shirataki noodles and continue to saute for another minute or so.
Add the vegetable stock, sake, sugar, soy sauce, and salt to the pan and bring to a boil. Cook until all the liquid is gone and the carrots are tender (about 10 minutes).
Pour the mixture into a sieve and let any remaining liquid drain while you prepare the other components.
Add the simmered vegetables from step 10 along with the toasted sesame seeds to the prepared sushi rice and fold into the rice.
You can either serve this on a large platter/bowl with the marinated peppers, snap peas and benishoga scattered on top, or you can plate individual portions and arrange the vegetables on top as seen in the photos.