Remove the flesh of the watermelon from the hard side. Cut the flesh into small bite sized pieces. Pick out the seeds and store the juice in a small separate bowl.
Half the cucumber and remove the seeds. Cut the remaining flesh into small cubes. Combine the watermelon, cucumber and olives in a large bowl.
Rinse and dry the feta cheese. Crumble it into a small bowl and add the watermelon juice to it along with yogurt and dill. Mix together well so that the flavors meld well and the dressing has a smooth taste.
Scoop out the salad into four platters and sprinkle pepper over them. Garnish with dill. On the platter side, scoop out a spoonful of the dressing.
You can serve wholemeal bread with the salad if you want to make it more filling.