Make the salad dressing: Combine all ingredients in a screw-top jar. Secure lid. Shake until well combined.
Heat oil in a saucepan over medium heat. Cook bread, in 4 batches, turning, for 1 to 2 minutes or until crisp and golden. Transfer to a wire rack to drain.
Place tomatoes, cucumbers, pepper, radish, onions, parsley and mint in a large bowl. Sprinkle with sumac. Drizzle with dressing.
Toss gently to combine. Break bread into pieces. Add to salad. Toss gently and serve.
