Cook noodles 3 to 5 minutes in boiling water. Drain and rinse in cold running water. Set aside.
Combine soy sauce, peanut butter, and brown sugar in a small bowl. Whisk to a uniform paste. Set aside.
Cut tofu into strips and pat dry on a paper towel. Heat 2 tablespoons of canola oil in a wok. Add tofu and stir fry until lightly brown. Place cooked tofu on a paper towel to absorb excess oil.
Wipe wok clean and heat a tablespoon of oil. Add beaten eggs and scamble until dry. Remove to a paper towel to absorb excess oil.
Wipe wok clean and heat two tablespoons of oil. Add scallions, bean sprouts, garlic, and red pepper. Stir fry for a minute or so. Add the cooked, drained noodles. Stir fry about five minutes, combining everything as uniformly as possible. Add the peanut butter paste and the vinegar. Stir and cook a few more minutes. Stir in cooked tofu and eggs.
Serve, topped with peanuts and accompanied by lime wedges.