Heat the oil in a heavy saucepan. Add the onion, garlic and ginger, and sweat over a gentle heat, stirring frequently, for about 5 minutes until softened.
Stir in the ground cumin, coriander, chilli powder and turmeric, and fry for 2 minutes until aromatic. Add the chickpeas, tomatoes and sugar. Season with salt, and stir to combine the ingredients. Cover the pan and simmer the curry gently, stirring occasionally, for 10 minutes.
Stir in 1 tablespoon of the lime juice and the torn coriander leaves, and heat through for a further 2 minutes. Taste the curry and add the remaining lime juice and more salt if necessary. Serve hot.