Cook the melon/ gourd and green chillies in about 1/2 cup boiling water till it is fully cooked but still maintains its shape.
Wash and cook the beans well – pressure cooking may work out the best. Add the beans to the cooked melon, add coconut milk, curry leaves and salt to it. Let it almost come to a boil and remove from heat.
Pour the coconut oil over it when it is is still hot so as to release the flavors.
I usually do not temper any seasonings for olan but if you want you can temper some mustard seeds and dried red chillies and pour over the olan as well.