Trim choy sum and wash thoroughly.
Heat peanut oil in a hot wok until surface seems to shimmer slightly. Add salt and garlic and stir-fry for 10 seconds. Add bok choy and stir-fry for 1½ minutes.
Add shao hsing wine and stir-fry for 30 seconds. Add water and stir-fry for a further 30 seconds or until leaves are just tender. Stir in sesame oil and serve immediately.
Any other Chinese greens, such as bok choy or gai lan, would also work well in this simple stir-fry.