Heat the oil in a heavy-bottomed pan on medium level and crackle the mustard seeds. Add the curry leaves, chopped green chillies and ginger. Fry lightly. Add the chopped onions and fry on medium level for about 2 minute(s).
Mix in the french beans(I usually boil them for a fewminutes or microwave them for 5 mins or so to remove the raw taste), turmeric and salt. Sprinkle the water and cook covered on low level for about 10 minutes or till the beans are cooked but firm. Mix in the grated coconut. Sprinkle the lemon juice before serving (optional).
Serve hot with White rice , chapathi or Warm dinner rolls.