Season your shrimp with a good amount of salt and the turmeric powder. Set aside.
In a pot, heat up your oil to a high heat and add your mustard seeds. You should hear them crackle. Next add your ginger, chili peppers, garlic, curry leaves, and onion in that order, stirring after each ingredient is added. Cook until the onions have become soft and the pepper is blistering. Then add your coconut milk and a good pinch of salt. When the coconut milk begins to bubble lightly add the shrimp. Cook for 5 minutes. Finish with your coriander, tomato, and toasted coconut.