Rinse quinoa under cold water. Cook in a saucepan with 2 cups water. Bring to a boil then cover, reduce heat, and simmer for about 15 minutes until water is absorbed. Fluff with a fork and keep warm.
Preheat oven to 425°F (220°C). Toss diced sweet potatoes in 1 tablespoon olive oil, 1/2 tsp cumin, salt, and pepper. Spread on a baking sheet in a single layer. Roast for about 25 minutes until tender, turning once halfway through.
In a skillet, heat 1 tablespoon olive oil over medium heat. Add chickpeas with turmeric, the remaining 1/2 tsp cumin, salt, and pepper. Sauté for about 10 minutes until chickpeas get crispy and golden.
Whisk together tahini, yogurt, lemon juice, a pinch of salt, and enough water to reach desired drizzle consistency. Taste and adjust lemon or salt.
Assemble bowls by layering quinoa as the base followed by roasted sweet potatoes and crispy chickpeas. Top with spinach leaves and avocado slices. Drizzle with tahini yogurt sauce and finish with black pepper.
Serve warm or at room temperature. If making ahead, keep sauce separate until serving.
Notes
For extra crunch, roast chickpeas for a few minutes on a separate tray while sweet potatoes finish. Store components separately to maintain texture if making ahead.