Make the dressing. In a large bowl, whisk together the Dijon, lemon juice, garlic, Aleppo pepper, sumac, and salt and pepper (about ½ teaspoon each). Whisk, and while whisking, drizzle in enough olive oil to make it nicely glossy and well-balanced. Continue to whisk until emulsified.
Mix. To the bowl with the dressing, add the chickpeas, cucumbers, tomatoes, roasted bell peppers, onion, parsley, and mint. Toss gently. Add the avocado and toss very gently once more.
Enjoy! Taste and adjust the seasoning to your liking and serve immediately.
