Cook noodles according to package instructions; set aside.
Combine coconut milk and red bell peppers in blender until smooth; set aside.
Heat canola oil in a large stockpot or Dutch oven over medium heat. Add garlic and shallot, and cook, stirring frequently, until tender, about 3-4 minutes.
Stir in red curry paste, ginger and chili powder until fragrant, about 1 minute.
Stir in chicken stock and coconut milk mixture, scraping any browned bits from the bottom of the pot.
Stir in chicken, fish sauce, soy sauce and brown sugar. Bring to a boil; reduce heat and cook, stirring occasionally, until slightly reduced and chicken is tender, about 15-20 minutes.
Remove chicken and shred, using two forks, before returning to the pot; stir in lime juice.
Serve immediately with noodles, garnished with red onion, bean sprouts, cilantro and lime, if desired.