Just as when you are grilling jumbo prawns on the barbeque, they key to proper wok cooking of jumbo prawns (or shrimp) is to not overcook them. The secret to wok cooking of prawns (and perhaps the secret to wok cooking in general) is to add the prawns to the wok at the right time. For wok cooking of prawns - which cook fast and are starting already at room temperature - it is important to add them to the wok very near the end of the time you are cooking.
Cooking Prawns in a Wok | How To
Cooking Prawns in a Wok | The Jumbo Prawns
Last but not least, we need to consider preparation of the actual Jumbo Prawns for our wok jumbo prawn recipes - fresh jumbo prawns or frozen jumbo prawns or shrimps both.