Toast the paprika in a small dry pan over medium heat, moving it around in the pan with a wooden spoon until a waft of it smells pungent and alive again, about 4 minutes.
In a high-powered blender or food processor, combine the watermelon, strawberries, tomatoes, onion and Worcestershire sauce. Blend until smooth and chill.
To make the garnish, on a cutting board, chop the basil, feta cheese and pine nuts all together until minced and combined. Serve the chilled soup with a sprinkle of the garnish on top.