Heat the oil in a large saucepan over a low heat, then add the onion and garlic and cook, stirring, for five minutes. Add the ginger, chillies, cumin, coriander and garam masala. Cook for a further two minutes.
Add the tomatoes, tamarind and spinach. Increase the heat to medium, and cook until the spinach has thawed and any liquid has been absorbed - about five minutes.
Stir in the chickpeas, salt and paprika and cook for three minutes, then serve.