Preheat some vegetable oil in a large pan or wok over medium-high heat. Then add the shrimp, yellow onion, garlic, and ginger. Sauté for around 2 minutes.
2 tablespoons vegetable oil, 1 pound shrimp, 1 small yellow onion, 3 garlic cloves, ½ tablespoon minced ginger
Next, add the frozen peas and carrots, cold rice, green onions, soy sauce, oyster sauce, ketchup, red chili flakes, and black pepper. Stir fry for 2-3 minutes. Season with salt if needed.
4 ½ cups cold cooked white rice, 2 cups frozen peas and carrots, 2 green onions, 2 tablespoons soy sauce, 2 tablespoons ketchup, ½ - 1 teaspoon red chili flakes, salt and pepper, 2 tablespoons oyster sauce