soak chiles in hot water for 15 minutes. drain. heat oil and saute onions until soft. add celery, garlic, chiles, and pimiento. saute for 5 minutes. stir in shrimp and saute until pink. remove and reserve. add tomatoes, coconut milk, palm oil and spices. bring to a boil, reduce heat and simmer until mixture thickens, about 10 minutes. return shrimp, stir in lemon juice and season with salt and pepper. garnish with cilantro and serve on rice.