Rinse the rice in clean water three times, or until the water runs clear.
Soak the rice in water for at least 20 minutes.
Drain the rice thoroughly using a fine sieve or colander.
Place the abura-age sheet in a bowl and pour boiling water over it. Let it soak for 30 seconds.
Rinse the abura-age under cold water to remove excess oil, then gently squeeze out the water with your hands.
Cut the abura-age into four equal pieces.
Then slice into thin strips (about 2mm by 4cm). Set aside.
Drain and rinse the sansai mizuni under running water. Set aside.
Transfer the drained rice to your rice cooker or saucepan and add the vegan dashi, mirin, soy sauce, sake, and salt to the rice. Stir to combine.
Layer the mountain vegetables and abura-age strips on top of the rice mixture.
If using a rice cooker, start the cooking process and let it complete. If cooking on the stovetop, cover the saucepan with a lid, bring it to a simmer, then reduce the heat to the lowest setting. Cook for about 15–20 minutes until all the liquid is absorbed.
Once the rice is cooked, gently stir to evenly distribute the vegetables.
Serve in your favorite rice bowl and, if desired, sprinkle with gomashio (a sesame and salt blend) for added flavor.