Preheat oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a large bowl, toss cauliflower florets with olive oil, shawarma spice blend, salt, and pepper until evenly coated.
Spread seasoned cauliflower on the baking sheet in a single layer and roast for 25-30 minutes, flipping halfway through until golden brown and tender.
While the cauliflower roasts, prepare quinoa or rice according to package instructions.
In serving bowls, layer cooked quinoa or rice at the bottom, then top with roasted cauliflower and chickpeas. Arrange pita triangles around the edge.
Drizzle tahini sauce over each bowl before serving.