Preheat oven to 200°C (180°C fan-forced). Place the bread on a baking tray and brush with the oil. Bake for 8-10 mins or until light golden and crisp. Set aside to cool. Break into coarse pieces.
Meanwhile, place the onion and vinegar in a small bowl. Set aside for 10 mins to soak.
To make the dressing, combine the lemon, oil, garlic and sumac in a small bowl. Season to taste.
Drain the onion and discard the vinegar. Place the tomatoes, cucumber and onion in a bowl. Add the dressing, half the mint and half the parsley and toss to combine.
Arrange the lettuce leaves on a serving platter. Top with the tomato mixture and drizzle over the dressing. Sprinkle with the remaining mint and parsley. Top with the bread. Sprinkle with the pomegranate, if using.
