In a bowl, mix the lime zest, five spice blend and 1 tbsp vegetable oil; marinate the prawns in this for at least 1 hour.
Combine the sweet chilli sauce, sriracha, fish sauce, lime juice and palm sugar in a bowl; taste and adjust to preferences.
Heat 1 tbsp oil in a wok to just smoking, add the prawns and cook on high for 2-3 minutes. Remove and keep aside.
Heat the remaining oil; sauté ginger and garlic on high and add the prawns back. Add the zucchini and bell peppers.
Add the mixed sauces to the prawns and cook for another 2-3 minutes.
Then add the tomatoes, taste and add salt if necessary.
Continue cooking till the sauce has coated the prawns well.
Add the pine nuts, mix and remove from heat.