Whisk together oil, garlic, ginger, citrus juice and zest. Season to taste.
Thread prawns, onions (halved if necessary) and Peppadews onto eight metal or pre-soaked wooden skewers. Place kebabs in a baking dish and pour ginger mixture over. Marinate at room temperature, turning occasionally, for 10 minutes.
Place kebabs on the braai, turning and basting with marinade occasionally, until lightly charred and cooked through (about four minutes).
Notes
Cooking prawns in their shells concentrates the flavour.