Wash hands with soap and water.
Scrub cantaloupe with clean vegetable brush under running water. Peel, seed and chop the cantaloupe.
Scrub cucumber with clean vegetable brush under running water. Peel and chop the cucumber.
Scrub onion with clean vegetable brush under running water. Peel and chop the onion.
Gently rub mint under cold running water and slice.
In blender, puree cantaloupe, cucumber, onion, salt and water until smooth, about 1–2 minutes.
With motor running, drizzle in olive oil. Sprinkle with freshly ground black pepper.
Serve gazpacho chilled, topped with mint slices.