Begin by soaking the rice noodles in room-temperature water first. The noodles should be submerged in plenty of water. By the time you are ready to put ingredients in the pan, the noodles should be flexible, but not completely soft. When in doubt, under-soak. You can always cook the noodles in the pan later.
Heat up a wok or cast-iron pan over high heat. Add the peanut oil, shallots, garlic, and tofu, and stir all the ingredients until fragrant and caramelized.
Add the tamarind paste, palm sugar, and fish sauce. Stir again.
Drain the rice noodles and add them to the pan. Stir quickly to keep things from sticking. The heat should remain high. If your pan isn't hot enough, you will see a lot of liquid in the wok at this point. Turn up the heat, if it is the case. The noodles should be now soft and chewy (not mushy). If they're still hard (under-cooked), add a little bit of water and continue to cook them.
Add the Chinese chives and bean sprouts. Stir a few times until all the noodles and the vegetables are coated in the Thai sauce.
Pour onto the serving plate and sprinkle with peanuts and dried chili pepper flakes. Serve hot with a wedge of lime, raw Chinese chives, and bean sprouts on top.
Store leftover pad Thai covered in the refrigerator for 3-4 days.
Vegan Fish Sauce
Combine wakame, garlic, peppercorns, soy sauce, shiitake mushrooms, and water in a large sauce pan and bring to a boil. Lower heat and simmer about 20 minutes (until the mixture is reduced and very salty). Strain and stir in the miso paste. Keep leftovers in the refrigerator.