It is called khao mun gai which is basically chicken on rice.

Chinese Chicken Rice is quite easy to prepare. All you have to do is place the chicken in a pot, add water, salt and coriander roots, and cook over a low heat until done. Skim off any froth to get the clear broth. Remove the chicken, de-bone and cut into slices. Strain the broth and set aside. Then wash the rice, drain and set aside. Heat some oil in a wok, fry the garlic over medium heat until fragrant and golden. Add the rice, stirring well and cook for 3 minutes. Transfer to an electric rice cooker, pour two cups of chicken broth over the rice and cook until the rice is done. Spoon the rice onto a serving dish, arrange the chicken slices on top, garnish with sliced cucumber.