Cook the Noodles:
Cook the rice noodles according to the package instructions. Drain and set aside.
Prepare the Sauce:
In a small bowl, whisk together soy sauce, brown sugar, rice vinegar, lime juice, peanut butter, and chili paste. Adjust the seasoning to your taste. Set the sauce aside.
Cook the Tofu:
In a wok or large frying pan, heat 1 tablespoon of oil over medium-high heat. Add the tofu cubes and cook until golden and crispy on all sides, about 5-7 minutes. Remove the tofu from the pan and set aside.
Stir-Fry the Vegetables:
In the same pan, add the remaining tablespoon of oil. Add the carrots and bell pepper, and stir-fry for 2-3 minutes until just tender. Push the vegetables to the side of the pan. If using eggs, crack them into the pan and scramble until cooked through.
Combine the Noodles and Sauce:
Add the cooked rice noodles to the pan with the vegetables. Pour the sauce over the noodles and toss everything together until well-coated.
Add the Tofu and Garnish:
Return the tofu to the pan and toss everything to combine. Remove from heat and top with bean sprouts, green onions, and chopped peanuts. Serve with lime wedges on the side.