Rinse the basmati rice and put it in a wide saucepan. Put the chicken breasts on top and push them down into the rice, then poke the ginger and garlic in around them. Pour the soy sauce over and add enough stock just to cover the chicken. Bring to a boil, cover and simmer for 8-10 minutes or until the rice is tender and the chicken is cooked through. Toss the cucumber with the sesame seeds and a sprinkle of salt. Serve the chicken sliced on top of the rice with the cucumber and chilli sauce.