Slice shitake, shimeji and enoki mushrooms into smaller clumps. Halve oyster mushrooms.
In a wok, heat vegetable oil on high. Add onions, shiitake, shimeji and oyster mushrooms, ginger, soy sauce and sesame oil. Stir-fry 2 minutes on high, until mushrooms are tender. Stir in enoki mushrooms and cook for 1 minute.