Place the chickpeas into a large container and cover with several inches of cool water; allow to soak for 8 hours or overnight. Drain.

Combine the chickpeas and 3 cups water in a large pot over medium heat; cook until the chickpeas are tender, but not yet mushy, 30 to 45 minutes. Drain.

Heat the oil in a skillet over medium heat. Fry the urad dal, mustard seeds, and dried red chile peppers in the hot oil. When the seeds begin to splutter, add the chickpeas, green chile peppers, mango, coconut, curry leaves, and asafoetida powder; season with salt. Mix well and cook until completely heated, 2 to 3 minutes. Remove from heat and add the lemon juice. Serve warm or at room temperature.