Adjust oven rack to middle position and preheat oven to 400°F. Line a rimmed baking sheet with parchment paper.
If making homemade spice blend, combine all spice blend ingredients in a small bowl and stir to combine.
Pat chickpeas dry with a clean kitchen towel or paper towels. In a large bowl, combine chickpeas with 1 tablespoon shawarma spice blend. Drizzle with olive oil and toss until evenly coated.
Spread chickpeas in a single layer on the prepared baking sheet. Roast until golden and lightly crisped, 20 to 22 minutes, stirring once halfway through. For extra crispness, broil for 1-2 minutes at the end (watch carefully).
Divide chickpeas among warm tortillas. Top with Greek yogurt, red onion, and avocado slices. Serve immediately.
Notes
To make spice blend: Combine all Shawarma Spice Blend ingredients in a small bowl before adding to the chickpeas in Step 2.
Shawarma spice blends vary; adjust salt to taste after roasting.
Roasted chickpeas are best served immediately to retain crispness.
Leftovers can be used in bowls with rice, greens, and pickled vegetables for an easy second-day lunch.