01 - Preheat the oven to 425°F. Line two baking sheets with parchment paper.
02 - Spread the diced bell pepper, sliced red onion, zucchini, and cauliflower florets on one baking sheet. Drizzle with 1 tablespoon olive oil, season with salt and black pepper, and toss to coat evenly.
03 - In a mixing bowl, combine the drained chickpeas with the remaining 1 tablespoon olive oil, ground cumin, coriander, smoked paprika, cinnamon, cayenne pepper (if using), salt, and black pepper. Toss until the chickpeas are thoroughly coated. Spread in an even layer on the second baking sheet.
04 - Place both baking sheets in the oven and roast for 20 to 25 minutes, tossing halfway through, until the vegetables are tender and the chickpeas are golden and slightly crispy.
05 - While the vegetables and chickpeas roast, whisk together the tahini, lemon juice, minced garlic, water, ground cumin, and salt in a bowl until smooth. Add additional water as needed to reach a pourable, drizzleable consistency.
06 - Divide the cooked quinoa or rice among four bowls. Arrange the roasted vegetables and spiced chickpeas over the grains. Drizzle generously with the lemon-tahini sauce and finish with a scattering of fresh herbs and lemon wedges on the side.