To make paste: Heat oil in skillet, add all of the paste ingredients and fry for 5 minutes. Transfer ingredients to a blender, add water, cilantro, turmeric and shimp paste and blend until smooth. Set aside. In heavy pot, heat oil, saute chicken, onion and potatoes until golden brown. This may have to be done in batches or in two separate pots. Add remaining ingredients and bring to a simmer. Simmer for 20 minutes and serve over rice.