Preheat oven to 400°. Arrange bread in an even layer on a rimmed baking sheet. Bake until golden and lightly crisped, about 9 minutes; let cool.
Whisk oil, vinegar, brine, garlic, and oregano in a large bowl; season with kosher salt and pepper. Add Peppadews, cantaloupe, and toasted bread and toss to combine. Let sit, tossing occasionally, at least 15 minutes and up to 1 hour.
Arrange salad on a platter and sprinkle with sea salt.