1. In a food processor, combine onions, garlic hot pepper and ginger. Pulse until finely chopped. Place oil in a large sauté pan over medium-low heat. Add chopped onion mixture and sauté until softened, about 5 minutes.
2. Add hot pepper flakes, and spices. Stir to mix. Add sweet potatoes and stir until well covered in spices. Stir in coconut milk.
3. Dissolve tamarind paste in hot broth and add to pan. Bring to boil, then reduce heat and simmer, partially covered, until sweet potatoes are just tender, about 25 minutes
4. Add chickpeas and simmer until heated through, about 5 minutes. Adjust salt to taste. Transfer to a warmed bowl and sprinkle with chopped cilantro.