Place the first 6 ingredients in a small bowl. Place the oil in a large skillet or wok set over medium-high heat. Add the prawns and cook 1 to 2 minutes per side, or until just cooked through. Add the mixture in the bowl and cook and toss the prawns until nicely coated and glazed. Spoon the prawns onto a platter, sprinkle with green onions, and serve.