Soak rice noodles in hot water for about 10 minutes, until flexible but firm. Drain well.

Heat a wok or large skillet over medium-high heat until it starts to smoke.

Add vegetable oil to the wok and heat until it shimmers.

Add peanuts to the wok and cook until roasted, stirring constantly for 1 to 2 minutes. Remove peanuts from the wok and set aside.

Add chile peppers, shallot, and garlic to the wok. Cook and stir until the garlic just begins to brown, about 30 seconds.

Add chicken and tofu to the wok. Cook until the chicken is no longer pink in the center and the juices run clear, about 4 to 5 minutes.

Add the drained noodles to the wok, stirring quickly to mix them in and prevent sticking.

Add sugar, tamarind paste, fish sauce, and white pepper to the wok. Cook, stirring constantly, until the sauce thickens, about 2 minutes.

Push the noodle mixture to one side of the wok.

Crack the egg into the empty space in the wok. Stir until scrambled, about 1 to 2 minutes. Fold the scrambled egg into the noodles.

Add shrimp (if using) to the wok. Cook until the shrimp is opaque, about 2 to 3 minutes.

Add roasted peanuts, bean sprouts, chives, and lime juice to the wok. Cook and stir until the flavors combine, about 1 to 2 minutes more.

Serve immediately.