Preheat the oven to 425°F (220°C).
In a medium saucepan, combine the rinsed quinoa and 2 cups of water. Bring to a boil over medium-high heat, then reduce heat to low, cover, and simmer for 15 minutes or until the water is absorbed. Remove from heat and let it sit covered for 5 minutes, then fluff with a fork.
While the quinoa cooks, prepare the chicken. In a small bowl, mix the olive oil, ground cumin, smoked paprika, garlic powder, salt, and black pepper. Rub this spice mixture evenly over the chicken breasts.
Place the chicken breasts on a baking sheet lined with parchment paper or foil.
In a separate bowl, toss the chopped red bell pepper, zucchini, and broccoli florets with 1 tablespoon olive oil, 1/2 teaspoon salt, and 1/4 teaspoon black pepper.
Spread the vegetables on another baking sheet lined with parchment paper or foil.
Roast the chicken and vegetables in the preheated oven for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the vegetables are tender and slightly caramelized.
While the chicken and vegetables roast, prepare the lemon-tahini dressing. In a small bowl, whisk together the tahini, fresh lemon juice, water, maple syrup, and minced garlic until smooth. Add more water if needed to reach a pourable consistency.
Once the chicken is cooked, let it rest for 5 minutes, then slice into strips.
To assemble the meal prep bowls, divide the cooked quinoa evenly among four meal prep containers.
Top each container with equal portions of roasted vegetables, sliced chicken, and baby spinach leaves.
Drizzle the lemon-tahini dressing over each bowl and sprinkle with chopped fresh parsley.
Seal the containers and store in the refrigerator for up to 4 days. Reheat before eating if desired.