Add 2 tablespoons of the canola oil and the chopped onion to a skillet and sauté over medium heat until the onion is translucent, about 5 minutes, then transfer it to a small bowl and set aside.

Combine the tofu and potato starch in a bowl. Stir well to coat the tofu pieces completely.

Sauté the tofu in the remaining canola oil in the empty skillet until the tofu turns crispy and golden brown, about 5 minutes. Drizzle with the sesame oil and add the onion, then reduce the heat to low and add the teriyaki sauce. Mix well.

Divide the rice between two bowls and top with the tofu mixture. Drizzle with the mayonnaise, if using, and sprinkle with the sesame seeds and microgreens before serving.

Add the tofu and lemon juice to a blender and blend until just smooth.

Add the sugar, kombu dashi powder, and rice vinegar to a small bowl and stir until the sugar is dissolved, then pour it all into the tofu mixture and blend until well combined.

With the blender running, gradually drizzle in the oil to create an emulsion. (If you want a thicker mayonnaise, continue adding more oil until the desired texture is achieved.)

Once you finish adding the oil, add the kala namak and blend just until combined.

Store the mayonnaise in an airtight container in the refrigerator for up to 1 week.