Blend all piri-piri ingredients except prawns in a food processor until smooth.
Rub the prawns with the piri-piri sauce, reserving some for garnish.
Marinate the prawns in the refrigerator for one hour.
Heat a griddle pan and cook prawns for 4 to 5 minutes on each side until pink.
Combine couscous and 400ml boiling water in a bowl.
Stir in the harissa, pomegranate molasses, baharat, and lemon juice.
Cover with cling film and set aside for 4 minutes until liquid is absorbed.
Fluff with a fork and mix in the red onion, pomegranate seeds, and coriander.
Serve prawns over couscous and drizzle with reserved sauce and lemon.