If using rice noodles, soak them according to package directions. If using regular pasta, cook, then drain, rinse, and set aside.
In a small bowl, combine the soy sauce, lime juice, sugar, ketchup, crushed red pepper flakes, and peanut butter. Whisk until uniform. Set aside.
Heat the oil in a wok or large skillet. Add the cubed tofu, and fry until golden and beginning to get crisp on all sides. Remove to a bowl, leaving the oil behind.
Add the garlic to the hot oil, cook for 10 seconds, then add the eggs and cook, stirring, until scrambled. Now add the drained noodles to the wok, mix well, and add the soy sauce mixture. Cook, stirring constantly, until the noodles are soft and tender, just a few minutes. You can add up to 1/4 cup of water if the mixture seems too dry.
Stir in bean spouts, green onions, and fried tofu. Fry for a minute or two. Taste for seasoning, adding more lime or chili if desired.
Serve sprinkled with chopped cilantro, additional bean sprouts, and a wedge of lime, if you're feeling fancy.