Preheat the oven to 425°F (220°C) and line a large baking sheet with parchment paper.
Toss the sweet potato, chickpeas, broccoli, and bell pepper with olive oil, smoked paprika, garlic powder, salt, and pepper, then spread in a single layer on the baking sheet.
Roast for 20-25 minutes, stirring halfway through, until the vegetables are tender and lightly browned.
Meanwhile, whisk together the tahini, lemon juice, water, and maple syrup until smooth, adding more water as needed to reach a pourable consistency.
Divide the cooked quinoa among bowls, top with the roasted vegetables, drizzle with tahini dressing, and garnish with fresh parsley.