Mix half oil with garlic, ginger, turmeric, cumin, coriander, cayenne, tamarind, sugar, chili, and 1/2 tsp salt to form a paste
Heat remaining oil in a wok. Add spice paste and stir for 30 seconds
Add crab to wok and stir so that spice mix gets all over crab pieces
Add 1/4 cup water, stir well, cover and cook 5-6 minutes until done
Serve with some of the liquid and garnish with cilantro