Place the rice noodles in a bowl and cover with hot tap water. Soak until the noodles have softened, about 5 minutes and then drain.
Heat a large skillet (frying pan) on medium high heat. When hot, drizzle with oil and add the onions. Cook until softened, 2-3 minutes and then add the cabbage. Drizzle with a bit more oil, season with 1 teaspoon of sea salt and a big pinch of white pepper. Cook until the cabbage is soft and a little caramelized, 3-4 minutes.
Add the noodles and tofu, along with the sesame oil and soy sauce or tamari. Season well with more sea salt and pepper. Toss until the noodles are have softened, with some charred bits, about 4-5 minutes.
To serve, top with scallions, coriander/cilantro and more sesame seeds.