Watermelon Cucumber Slushy

Purée 1 lb. seedless watermelon, rind removed, flesh cut into large cubes, 2½ oz. cucumber, peeled, ¼ cup honey, 1 Tbsp Champagne vinegar, and ¼ tsp. Diamond Crystal or Morton kosher salt in a blender until smooth. Add 4 cups crushed ice and blend on high just until slushy (be sure you’ve crushed the ice if starting from large pieces). The slushy should be spoonable, like soft ice cream.

Divide slushy among 6 tall glasses and garnish each with a cucumber spear.