01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - Toss sweet potato cubes with olive oil, salt, and pepper. Arrange evenly on the prepared baking sheet. Roast for 25 to 30 minutes, stirring halfway through, until caramelized and tender.
03 - In a saucepan, combine quinoa, water, and salt. Bring to a boil, then reduce heat, cover, and simmer for 15 minutes. Remove from heat and let rest, covered, for 5 minutes. Fluff with a fork to separate the grains.
04 - In a mixing bowl, combine tahini, lemon juice, water, olive oil, maple syrup or honey, minced garlic, salt, and pepper. Whisk until completely smooth, adjusting water to achieve preferred consistency.
05 - Divide baby spinach or mixed greens evenly among four bowls. Top each with a serving of quinoa, roasted sweet potatoes, cherry tomatoes, sliced red onion, and avocado.
06 - Drizzle each bowl with lemon-tahini dressing. Sprinkle with feta cheese, seeds, and herbs as desired. Serve immediately.