Season the chicken pieces and set aside. Process the onion, garlic and ginger in a food processor until smooth. If necessary, add a little water to assist in blending the mixture. Heat the oil in a large pan. Add the onion mixture and shrimp paste and cook, stirring, over a high heat for about 5 minutes.
Add the chicken and cook over a medium heat, turning it until it browns.
Pour in the coconut milk and add the curry powder. Bring to the boil, reduce the heat and simmer, covered, for about 30 minutes, stirring from time to time. Uncover the pan and cook for a further 15 minutes or until the chicken is tender.
Place the noodles in a bowl, cover with boiling water and set aside for 10 minutes. Drain the noodles and divide them between 4 large warmed serving bowls. Ladle over the curry, and garnish with chopped coriander, chopped red onion, fried garlic slivers, sliced red chillies and lime wedges.