Combine the peas, turmeric and 7 cups of the water in a heavy-bottomed 6 quart or larger stockpot or Dutch oven over medium-high heat and bring to a boil.
Reduce heat to medium-low, partially cover, and simmer for 30-40 minutes, until the peas soften. Remove from heat and let stand while preparing the remaining ingredients - they do not need to be drained.
Soak the tamarind pulp in the remaining cup of water for 30 minutes. Break apart with a fork and squeeze the pulp with your hand. Strain through a fine strainer, discarding the solids.
Place the tamarind juice and tomato in a food processor and grind into a watery paste. Reserve.
Warm coconut oil in an 8-in skillet over medium-high heat. Add the onion and cook for 6-7 minutes until browned and caramelized. Add the ginger and garlic and cook for 1 minute.
Slowly and carefully add the tamarind-tomato paste, the fresh chiles and the brown sugar to the frying pan. Stir well and cook for 4 minutes. Remove from the heat and transfer the mixture to the stockpot with the black-eyed peas.
Return the stockpot to medium-high heat and add the coriander, red chile powder and salt. SImmer, uncovered, for 10 minutes.
Add the coconut milk and cook for 1 minute or so, until warmed through. Remove from heat.
Transfer to a serving bowl. Garnish with the cilantro. Serve with white or brown basmati rice, roti or naan.