Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Chop the zucchini, red bell pepper, and red onion into uniform 1-inch pieces to ensure even roasting.
Toss the chopped vegetables on the baking sheet with 0.5 tablespoons of olive oil, 0.25 teaspoons of sea salt, and the black pepper.
Roast the vegetables for 20 minutes, adding the cherry tomatoes to the sheet during the final 5 minutes until they begin to burst.
While vegetables roast, rinse the quinoa under cold water and combine it in a small saucepan with 0.5 cups of water.
Bring the quinoa to a boil, then reduce heat to low, cover, and simmer for 15 minutes or until all water is absorbed and the grain is fluffy.
Season the chicken breast on both sides with the dried oregano, garlic powder, and the remaining 0.25 teaspoons of sea salt.
Heat the remaining 0.5 tablespoons of olive oil in a cast-iron skillet over medium-high heat and sear the chicken for 6-7 minutes per side until golden and cooked through.
In a small bowl, whisk together the non-fat Greek yogurt, lemon juice, minced garlic clove, and finely chopped fresh dill to create a savory dressing.
Assemble the bowl by placing a base of baby spinach and cooked quinoa, then topping with the roasted vegetables and sliced chicken breast.
Garnish the bowl with crumbled feta cheese and Kalamata olives, then finish by drizzling the creamy lemon-yogurt sauce over the top.