Directions to make the dressing:
1. In a mixing bowl add the juice of one lime and the palm sugar, mix well with a whisk until dissolved. Add the white rum and Angostura bitters and mix until incorporated.
Directions to make the salad:
2. Halve the cucumber length ways, scoop out the seeds and discard. Diagonally cut the cucumber into 1 cm, ½ inch pieces and transfer into a large mixing bowl.
3. Cut the watermelon in half and remove the rind by running a large knife down the outside of the watermelon flesh. Vertically divide the watermelon into three and cut the flesh into 2.5 cm, 1 inch chunks. Place in the mixing bowl, you should roughly have equal quantities of cucumber and watermelon. Add the prawns to the mixing bowl.
4. Just before serving, pour over the dressing and most of the chopped coriander and mint leaves, toss well in the bowl.
Plate three handfuls of salad on each plate, drizzle with a couple of teaspoons of dressing and garnish with a pinch of the remaining herbs.
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