1. Place the prawns and smoked salmon in a bowl and toss with the chilli, lime zest and 1 tbsp lime juice. Season generously. Mix mayonnaise and remaining lime juice in a separate bowl.
2. Thinly slice the cucumber diagonally. Place one slice of cucumber upright in each serving glass, then cut the remaining slices in half and arrange in the bottom of the glasses.
3. Divide the rocket or watercress between the glasses, placing on top of the cucumber.
4. Spoon the prawn and salmon mixture over the leaves. Drizzle the cocktails with lime mayonnaise, dust with a little paprika (optional), before serving with lime wedges.