Preheat oven to 375 F.
Combine cauliflower, oil, garlic, salt and pepper and toss to combine.
Place in a baking dish and roast for 30 minutes, until fork tender but still crisp.
Combine bread and olive oil. Toss to combine.
Place on a cookie sheet in a single layer and bake for 30 minutes or until bread is crispy.
To make the dressing, combine lemon juice, salt and pepper. Whisk well. Slowly drizzle in olive oil while whisking constantly.
In a large bowl, combine bell pepper, lettuce, tomatoes, cucumber, scallion, mint and parsley. Toss to combine.
Add cauliflower and bread. Add salad dressing and toss well.
To serve, garnish with sumac.