Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper.

Cook the quinoa: In a medium saucepan, combine quinoa and water. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes or until water is absorbed. Fluff with a fork and set aside.

Prepare the vegetables: Place sweet potato, broccoli, cauliflower, and zucchini on the baking sheet. Drizzle with olive oil and sprinkle with cumin, smoked paprika, garlic powder, salt, and black pepper. Toss to coat evenly.

Roast the vegetables: Spread the vegetables out in a single layer and roast in the oven for 25-30 minutes, stirring halfway through, until tender and slightly caramelized.

Prepare the tahini dressing: In a small bowl, whisk together tahini, lemon juice, maple syrup, and water until smooth. Adjust the consistency by adding more water if needed.

Assemble the bowls: Divide the cooked quinoa evenly among serving bowls. Top with roasted vegetables, chickpeas, sliced avocado, and a drizzle of tahini dressing.

Garnish with chopped parsley, if desired, and serve immediately.