Heat a skillet over medium heat. Add the coconut oil and the onion and cook until soft. Add the garlic and ginger and cook for 1 minute. Stir in the salt and curry powder and cook for another minute. Transfer to a slow cooker pot.
Add the sweet potatoes, stock, tomato puree and chickpeas. Stir and cover. Cook on low for 6-8 hours. Stir in the coconut milk and lime juice.
Serve over the brown rice, topped with the cilantro and yogurt.