The key to success with a stir fry is to have all of the ingredients prepped ahead of time and lined up next to your cooking area. Vegetables cut, chicken sliced, garlic minced, and other ingredients measured out. The actual cooking will happen very quickly over very high heat, over a period of about 5 minutes.
Start by tossing the thinly sliced chicken breast in the soy sauce, cornstarch, and rice vinegar. Let this sit for 2 minutes.
Heat up a large skillet for a few minutes over high heat for electric, medium high for a gas stove. Add the vegetable oil (it should shimmer in the pan, not smoke), garlic, red chili flakes, and grated ginger to the pan, then immediately add the chicken with its marinade. Let the chicken sit for 1 minute, then toss and stir it around for another minute longer. Add all of the vegetables (carrots, peppers, zucchini, scallions, baby corn, and water chestnuts) and the peanuts to the pan. Add a little sprinkle of salt and pepper, then stir and toss the vegetables in the hot pan for another 2-3 minutes. If the sauce gets too thin, add a couple tablespoons of chicken stock to reconstitute the sauce. Check that the chicken is cooked through, then taste the chicken and vegetables. Make any necessary seasoning adjustments, drizzle on some sesame oil to taste, then serve with rice. Enjoy!