Preheat your oven to 400°F (200°C). Peel and cube the sweet potato. Slice the bell pepper into strips and place both on a baking sheet along with the broccoli florets. Drizzle with 1 tbsp of olive oil, and season with salt and pepper. Roast for 25-30 minutes, flipping halfway through, until tender and slightly browned.

While the vegetables are roasting, rinse the quinoa under cold water. In a medium saucepan, bring 1 1/2 cups water to a boil. Add the quinoa, reduce heat to low, cover, and simmer for 15 minutes or until the quinoa is cooked and fluffy. Remove from heat and let sit, covered, for 5 minutes, then fluff with a fork.

In a small bowl, combine 1 tbsp olive oil, the juice of half a lemon, minced garlic, paprika, dried oregano, salt, and pepper. Place the chicken breasts in a shallow dish or resealable bag, and pour the marinade over them, ensuring they are well coated. Let marinate for at least 10 minutes.

Heat a grill pan over medium-high heat. Remove the chicken from the marinade and grill for about 6-7 minutes on each side or until the internal temperature reaches 165°F (75°C). Once cooked, remove from the heat and let rest for a few minutes before slicing.

In a small bowl, whisk together the tahini, juice of the remaining lemon half, a tablespoon of water, and a pinch of salt until smooth. Adjust consistency with more water if needed.

Assemble the bowls: Divide the quinoa into two bowls, top with equal portions of roasted vegetables and sliced chicken. Drizzle each bowl with the tahini-lemon dressing. Serve immediately.