Halve the cucumber. Run a teaspoon down the middle to scoop out the seeds. Slice the cucumber into chunks around 1 cm thick. Pop in a non-metallic bowl. Gently bash a few times with the end of a rolling pin to slightly smush them.
Add 1 tbsp each of the sugar and rice vinegar to the cucumber with a pinch of salt. Give it a good stir. Set aside to pickle – juices will begin to run out of the cucumber as it pickles.
Peel and grate the garlic and ginger. Halve the chilli. Flick out the seeds and white bits for less heat (or leave them in), then finely chop it. Slice the thick cores out of the kale and finely slice the leaves. Rinse the rice under cold running water.
Warm 1 tbsp oil in a pan. Add the chicken. Fry, turning once or twice, for 5 mins till the chicken is lightly browned all over.
Stir in the garlic, ginger and chilli. Sizzle and stir for 1 min till the pan smells sweet and aromatic.
Stir in the rice. Pour in 400ml boiling water. Pop on the lid. Bring to the boil. Turn the heat right down. Simmer for 8-10 mins till the rice is tender and the water has been absorbed.
Stir the kale leaves into the rice, adding a splash more water if the rice is dry – it should be a little soupy. Cook and stir, without the lid on, for 3-4 mins till the kale is just wilted. Take off the heat.
Stir in half the tamari. Taste and add more tamari if you think it needs it. Fish the chicken out of the pan and chop it or pull it apart with two forks. Ladle the rice into warm bowls. Top with the chicken. Serve with the pickled cucumber on the side.