In a medium bowl, toss the peeled prawns with 1 tablespoon of soy sauce and the cornstarch. Set aside to marinate for 10 minutes while you prepare the remaining ingredients.

In a small bowl, whisk together the remaining 2 tablespoons of soy sauce, black vinegar, hoisin sauce, and sugar to create the stir-fry sauce. Set aside.

Heat the vegetable oil in a wok or large skillet over medium-high heat. Add the dried red chilies and stir-fry for about 30 seconds until they just begin to darken and become fragrant.

Add the marinated prawns to the wok and stir-fry for 2 to 3 minutes, or until they turn pink and opaque. Push the prawns to one side of the pan.

Add the minced garlic and grated ginger to the empty side of the pan, cooking for 30 seconds until highly aromatic. Toss everything together to combine.

Pour the prepared stir-fry sauce over the prawns, stirring constantly for 1 minute until the sauce thickens and beautifully coats the seafood.

Remove from heat, then stir in the roasted peanuts and chopped green onions. Serve immediately over hot steamed rice for a delicious, quick weeknight meal.