Heat a large wok or frying pan over a medium heat. Add the oil, then the onions, cooking until soft. Stir in the okra and chickpeas. Add the tomatoes and chilli, then season. Mix well and keep stirring gently, taking care not to break up the okra. Okra releases a sticky substance when cooked, but keep cooking, stirring gently – this will disappear and the tomatoes will become pulpy, about in 10 mins.