Preheat the oven to 400°F (200°C).
Rinse the quinoa under cold water. In a large pot, combine 1 cup of quinoa with 2 cups of water. Bring to a boil, then reduce heat to low, cover, and simmer for about 15 minutes, until quinoa is fluffy and water is absorbed. Remove from heat and let it sit covered for 5 minutes, then fluff with a fork.
While the quinoa is cooking, prepare the sweet potato. Toss the diced sweet potato with olive oil, paprika, garlic powder, salt, and pepper on a baking sheet. Roast in the oven for about 20-25 minutes or until tender and slightly crispy, turning halfway through.
In a small bowl, whisk together tahini, lemon juice, maple syrup (if using), salt, and enough water to reach your desired dressing consistency.
Assemble the Buddha bowls: Start with a base of quinoa, then add the roasted sweet potato, chickpeas, fresh spinach, cherry tomatoes, and avocado slices on top.
Drizzle the tahini dressing over the assembled bowls and serve immediately.