Heat the oil in a large wok or skillet over high heat.
Add the shrimp to the wok and cook until no longer translucent, approximately 2-3 minutes. Transfer to a separate plate.
Add garlic and onions, and cook for 2 minutes. Stir in the peppers and snap peas, and cook for 2-3 minutes.
In a medium bowl, whisk together soy sauce, rice vinegar, chili paste, oyster sauce, brown sugar, cornstarch, and water. Stir in the sauce mixture, stirring continuously, until the sauce has thickened.
Return the cooked shrimp to the wok and toss to coat well. Serve immediately.