Peel and chop the onions. Wash, clean and roughly dice the tomatoes. Heat the oil in a pot and fry the onions. Add tomato paste and sauté briefly. Add tomatoes and stock, cover and simmer for about 10 minutes.
Drain the chickpeas. Coarsely mash the soup, add the chickpeas and warm them up. Wash the coriander and dab dry. Set aside some coriander for garnishing. Chop the rest and stir into the soup.
Season with salt and pepper. Arrange soup in deep plates and garnish with coriander.