In a medium size bowl, zest one lemon and add the juice of both lemons. Next whisk in the orange juice, shallots, honey, salt, and pepper. Slowly pour in the olive oil, whisking constantly, to form an emulsion.
Place all salad ingredients (watermelon, cucumber, feta cheese, cherry tomatoes, arugula, mint leaves) into a large bowl or platter and drizzle enough vinaigrette to coat lightly and toss evenly. Serve immediately for a light lunch or refreshing starter to your meal.