Preheat the oven to 425°F. Line a large baking sheet with parchment paper. (Or use two smaller ones if you don't have an extra-large pan.)

Add the cauliflower florets, drained and patted-dry chickpeas, and sliced red onion directly onto a parchment-lined sheet pan (or divide between two smaller pans if needed). Drizzle everything with 6 tablespoons of olive oil and sprinkle with 3 tablespoons of Za'atar. Use your hands or a spatula to toss everything together right on the pan until evenly coated.

Roast for 25 minutes, until the cauliflower is browned and the chickpeas are crispy.

Meanwhile, whisk the tahini, lemon juice, maple syrup (or honey), cumin, salt, and pepper in a small bowl. Slowly stir in 4 to 5 tablespoons of ice water until smooth.

To serve, layer arugula on a serving platter, top with roasted cauliflower, chickpeas, and onion. Drizzle with tahini sauce, garnish with fresh parsley, and if you like a little heat, add a few pickled Fresno pepper slices on top.