Heat the oil in a large skillet or Dutch oven over medium-high heat. Sauté the onion in the skillet for a few minutes, until softened. Add the garlic and ginger, and cook for another minute.
Stir in the tomato paste, curry powder, garam masala, cumin, and turmeric. Cook for about 30 seconds until fragrant.
Add the diced tomatoes and cook for 2–3 minutes to reduce slightly.
Stir in the chickpeas, sweet potato, zucchini, and coconut milk. Season with the salt and pepper and bring to a low boil. Reduce heat, cover, and simmer for 15-20 minutes until the sweet potatoes are fork-tender and the curry has thickened.
Taste and add more salt and pepper, as needed. Serve over brown rice, quinoa, or riced cauliflower topped with fresh lime juice and cilantro.