Prepare the sauce: In a small bowl, whisk the soy sauce, cornstarch, garlic, ginger, and red pepper flakes. Set aside.
Heat the avocado oil in a wok or a large, deep skillet over medium-high heat for about 2 minutes.
Add the shrimp and vegetables and stir-fry until the vegetables are tender and the shrimp are cooked, 5-10 minutes. Larger shrimp and frozen veggies will take longer to cook.
Lower the heat to medium. Give the sauce another stir, then add it to the skillet. Cook, stirring, until the sauce thickens, about 1 minute.
Remove from the heat and transfer the dish to individual plates or a serving platter. Drizzle with sesame oil, sprinkle with sesame seeds, and serve.
