When you have broken up your purple onion segments into the crispy flavorful pieces for your chosen wok recipe, set them aside as you'll be adding them for most jumbo prawn wok recipes towards the end of the wokking around when the peas will go into the wok and before the jumbo prawns themselves go into the wok.
Purple Onion segments hand-cracked into pieces for the Wok
You want your onions to still be a bit crisp when the wok cooking is done, so you need to add them late in the cooking. You can follow the timing instructions in the wok recipes for guidance.