Place a large sauce pan or wok on high heat add the oil and heat for a minute. Add the curry paste stir for half a minute.
Add the coconut milk, sugar and the fish sauce and bring to a boil. Reduce the heat, add the chicken and the Kaffir leaves and simmer for 10 minutes.
In the meantime, place a medium pot on high heat, add the water and bring to a boil, Add the potatoes and cook for 5 minutes until tender. Add the beans and cook for further 7 minutes.
Remove the potatoes and the beans from the water and add to the chicken. Let absorb the flavours for 2 minutes while stiring and serve with the Basmati rice.