Heat the oil in a big casserole, add the garlic, leaves of coriander and zest of lime, then fry until fragrant for 2 minutes. Stir in the cumin and chilli flakes, fry the vegetables, beans and stock for 1 min more, then plug in. Use a potato masher to bring to the boil, then crush the beans several times against the bottom of the pan. This will somewhat thicken the soup.
Remove the kale into the soup, cook for 5 minutes or until tender, then break in the chicken and let it warm up. Season to taste with half the lemon salt, pepper and juice, then serve in shallow bowls, dispersed with the feta and a few leaves of coriander.