Other vegetables that you can easily add to this recipe: snow peas, canned straw mushrooms (halved), canned baby corn (cut small pieces), fresh bean sprouts, red bell pepper (julienned), julienned carrots. If you add more ingredients, increase the amount of seasoning and garlic/ginger/green onion.
In a small bowl, combine oyster sauce, soy sauce and cilantro and set aside.
Pat the shrimp very dry with paper towels. In a medium bowl, add shrimp and cornstarch and toss to coat.
In a wok or large saute pan over high heat, add half the cooking oil and swirl to coat the bottom of the pan. When the wok is very hot, add the shrimp in a single layer and cook partially until one side is nicely seared, about 1 minute. Flip and sear the other side of each shrimp, about one more minute. They don't need to be cooked all the way through yet. Remove them to a plate and set aside.
Turn the heat down to medium and let wok cool off a bit to prevent the aromatics from burning. Add the remaining cooking oil and add green onion, garlic and ginger and stir fry for a minute until fragrant. [If you are using other vegetables, like snow peas, add them to the wok now and stir fry for a minute or until the vegetables are bright in color and crisp-crunchy]
Pour in the sauce mixture and add the shrimp back into the pan. Stir fry for another minute or so until shrimp is cooked through. Serve immediately.