Preheat the oven to 425°F and line a baking sheet with parchment paper or a thin layer of oil.
Rinse the quinoa in a fine mesh sieve under cold water for about 30 seconds. Drain well, then add to a small saucepan with 1 1/2 cups water. Bring to a boil, reduce to low, cover and simmer until the water is absorbed, about 12–15 minutes.
Remove the pan from the heat and let the quinoa steam, covered, for 8 minutes. Fluff with a fork and set aside to cool slightly while you prepare the chickpeas.
Transfer the drained chickpeas to a bowl and toss with 1 tablespoon olive oil, smoked paprika, garlic powder, oregano, salt and pepper until evenly coated. Spread them in a single layer on the prepared sheet.
Roast the chickpeas for 18–22 minutes, shaking the pan or stirring once at the 10-minute mark so they crisp on all sides. Remove from the oven when golden and slightly crunchy; let cool a few minutes (they firm up as they cool).
Whisk together the lemon vinaigrette: combine 3 tablespoons olive oil, 2 tablespoons lemon juice, lemon zest, 1/2 teaspoon oregano, 1/4 teaspoon salt and a pinch of black pepper. Taste and adjust acidity or salt if needed.
Assemble bowls: divide about 1/2 cup cooked quinoa among 4 bowls. Add 1 cup greens, 1/4 cup cucumber, 1/4 cup halved tomatoes, 2 tablespoons red onion, 3 tablespoons crumbled feta and roughly 1 tablespoon olives to each bowl.
Top each bowl with a generous scoop of roasted chickpeas, a dollop of hummus, a drizzle of tzatziki and finish with the lemon vinaigrette and chopped parsley. Serve immediately.