Heat the oil in a medium stockpot and add the onion, celery, and carrot and cook until tender, about 6 minutes. Add the turmeric, cinnamon, ginger, cumin and black pepper and cook for 1 minute, stirring constantly to prevent scorching.Add the tomatoes with the juice, and sea salt. Cook until fragrant, about 2 minutes.Add the stock and sweet potato and bring to a boil. Reduce heat to low and simmer, covered for 20-25 minutes, until sweet potato is tender.Add chickpeas, cauli-rice, cilantro and parsley and cook until cauli-rice is tender, about 5 minutes. Add additional stock if you want it thinner. Stir in spinach leaves. Serve with a wedge of lemon for squeezing over each portion.