In a small mixing bowl, whisk together minced garlic, ginger, soy sauce, sugar, vinegar, sesame oil, water, and cornstarch. Set aside.
Heat canola oil in a wok or large skillet over medium-high heat. Add shrimp and cook 2-3 minutes, stirring frequently, until the shrimp just turns pink. It will continue to cook when making the sauce. Transfer to a plate and set aside.
Add onions to the skillet with more oil if needed. Cook for 2-3 minutes or until they begin to soften. Add the bell peppers, ginger and garlic and cook another 4-5 minutes or until the vegetable begin to soften.
Pour sauce into the skillet and cook for 1-2 minutes or until the sauce begins to thicken. Add the shrimp, red pepper flakes and peanuts to the skillet and cook for 1-2 more minutes, stirring occasionally.
Serve over rice topped with sesame seeds and sliced green onions (optional).
Storage - Leftovers can be stored in an airtight container for up to 4 days.Reheating - Leftovers can be reheated in a skillet on the stove over medium until warmed.