If the tofu contains a lot of moisture, press it for a few minutes (up to 20). Slice the tofu into strips or cubes, ¼ to ½ inches in width. Place the tofu in a shallow bowl, and then add the soy sauce and mirin. Coat the tofu and leave it for a few minutes to season.
Preheat the oven to 4200 F. (2200 C.). Sprinkle cornstarch over the tofu and toss it so that all sides are covered in cornstarch. You may want to use your hands to ensure that each piece is covered and the cornstarch is absorbed. Place the tofu pieces on a baking tray lined with parchment paper or a baking mat. Bake the tofu for 15 minutes, or until it starts to brown, then flip each piece and bake for another 10 minutes or until brown.
Heat a large skillet or wok. Add the onions and stir them almost constantly until they become translucent and begin to brown.
Mix in the ginger, garlic, and chili slices. Stir them for another 30 seconds so that they mix with the onions.
Add the cauliflower florets and cook them until they begin to brown. Add ¼ of a cup of water and cook them for a few minutes more until they are brown and tender.
Mix in the cumin, chili flakes, and salt. Then add the coriander and baked tofu.
Serve the stir fry over rice or noodles. Add toasted sesame seeds on top if desired.
