In a large skillet, heat oil over medium-high heat; saute onion until tender, 2-4 minutes. Add garlic, ginger and dry seasonings; cook and stir 1 minute. Stir in tomatoes; transfer to a 3- or 4-qt. slow cooker., Stir in chickpeas, potato and stock. Cook, covered, on low until potato is tender and flavors are blended, 6-8 hours., Stir in lime juice; sprinkle with cilantro. Serve with rice and, if desired, red onion and lime wedges.