In a food processor or blender, combine the feta cheese and cottage cheese. Blend until smooth. Add water 1 tablespoon at a time until the mixture reaches a creamy, spreadable consistency. Set aside or chill until ready to use.
In a large bowl, combine the diced watermelon, sliced cucumbers, lemon juice, mint, and a pinch of sea salt and black pepper. Toss gently to mix.
Spread the whipped feta on the bottom of a serving platter or individual plates. Top with the watermelon cucumber salad. Garnish with extra mint or a drizzle of olive oil if desired. Serve immediately.
