01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - Toss sweet potato cubes with olive oil, salt, and pepper. Spread on the prepared sheet and roast for 25 to 30 minutes, stirring halfway, until golden and tender.
03 - Combine quinoa, water, and salt in a saucepan. Bring to a boil; reduce to a simmer, cover, and cook for 15 minutes. Remove from heat, let stand 5 minutes, then fluff with a fork.
04 - In a small bowl, whisk together tahini, lemon juice, water, olive oil, maple syrup, garlic, salt, and pepper until smooth. Adjust water for desired consistency.
05 - Divide greens among four bowls. Top with quinoa, roasted sweet potatoes, cherry tomatoes, red onion, and avocado slices.
06 - Drizzle with lemon-tahini dressing. Garnish with feta, seeds, and fresh herbs if desired. Serve immediately.