Preheat oven to 425°F. Brush sliced ciabatta with olive oil. Toast until golden brown, about 6 minutes.
Wash and peel carrots. Halve and toss with olive oil, salt, oregano, and chili flake. Spread carrots out on sheet pan and roast until browned and softened, about 10 minutes.
Dry-toast walnuts in a pan on medium heat. Let cool and roughly chop.