Tip the rice into a bowl. Cover with cold water. Set aside to soak while you start the chicken curry.
Peel and finely chop the onion. Warm 2 tsp oil in a pan over a medium heat. Fry the chicken for 5-8 mins till golden brown. Stir now and then so it colours evenly. Lift the chicken out onto a plate.
Add the onion to the pan with a splash of water. Season. Turn the heat down to low and fry for 5 mins till the onion is soft and glossy. Stir now and then.
Add a pinch of the curry leaves to the pan. Measure out 1 tsp of the jerk seasoning and add to the pan. Fry and stir for 1 min till the pan smells aromatic.
Stir the chicken back into the pan. Pour in the chopped tomatoes. Half fill the tin with water and pour into the pan. Cover and bring to the boil. Turn the heat down. Simmer for 15-20 mins till the curry is thick. Stir now and then.
While the curry cooks, drain the rice. Tip into a small pan. Pour in the coconut milk. Add 200 ml boiling water and a pinch of salt. Stir, cover and bring to the boil.
Turn the heat down. Simmer for 8-10 mins till the water and coconut milk have been absorbed and the rice is tender.
Divide the rice and curry between two warm bowls or plates. Garnish with the coriander leaves to serve.