Trim, wash and dry the Chinese broccoli. Discard large central stems.  Steam the Chinese broccoli for 3-5 minutes, until crisp tender. Plunge into ice water to stop it from cooking.  Preheat a wok or sauté pan over high heat for 5 minutes.
Add peanut oil, swirl to coat the bottom of the wok. Then add garlic, ginger, chiles and scallions.  Toss and add the Chinese broccoli. Saute to heat the broccoli through, about 3 minutes.  Add the oyster sauce, tossing for 15 seconds. Garnish with toasted sesame seeds and serve immediately.