Heat the oil in a large frying pan over a medium heat. Add the cumin seeds and fry for 30 seconds or until they splutter. Watch carefully and stir constantly so that they do not burn.
Tip in the shallots and fry for 2 minutes until they are glazed. Add the green chillies and fry for a further 2 minutes. Tip in the green beans and the salt and saute for 5 minutes.
Sprinkle with the lemon juice and serve hot as an accompaniment.