Warm the pot over medium-high heat. Add the oil and swirl to coat. Add the onion and sauté until tender, about 5 minutes. Stir in the garam masala and cook just 30 seconds. Add the chickpeas, crushed tomatoes, and diced tomatoes. Cook until the beans are hot, about 5 to 10 minutes. Add the spinach and cook until it wilts, about 2 minutes. Remove from heat and stir in the yogurt and sea salt. Serve with rice and garnish with fresh cilantro.