Grind the soaked red chilies, ginger, garlic, onion, turmeric powder, cumin powder, coriander powder & poppy seeds. Heat oil in a pan and add the ground mixture and fry for 10 minutes with constant stirring. Add little water if it sticks to the pan. Then pour half of the coconut milk with 2 cups of water and simmer for 10 more minutes over low heat. Now add the crab claws & salt and cook for 3-4 minutes. Add the tamarind paste & the remaining coconut milk and bring it to a boil. Reduce the heat and cook until the crab is well cooked. Serve hot with rice.