Pat dry the cubed watermelon and the sliced cucumbers to remove excess water. This will help the salad be less watery.
Combine the cubed watermelon, sliced cucumbers, orange segments, sliced apricots, basil, mint, and arugula in a large serving bowl. Toss to combine.
In a small bowl, whisk together the lemon juice and olive oil until emulsified. Season to taste with sea salt and pepper. Drizzle on top of the salad and toss well to coat all the ingredients.