In a medium bowl, combine 3 tablespoons extra-virgin olive oil, 2 tablespoons fresh lemon juice, minced garlic, oregano, smoked paprika, cumin, and a generous pinch of salt and pepper. Add the chicken thighs and toss to coat thoroughly. Let marinate for at least 15-20 minutes, or up to 2 hours in the refrigerator for deeper flavor.

Rinse the quinoa under cold water in a fine-mesh strainer to remove the bitter saponin coating. Transfer to a saucepan, add 2 cups water and a pinch of salt. Bring to a boil, then reduce to a gentle simmer.

Cover the quinoa and cook for 15 minutes until water is absorbed and quinoa is fluffy. Remove from heat and let sit covered for 5 minutes, then fluff with a fork.

Heat a skillet or grill pan over medium-high heat. Remove chicken from marinade and cook for 5-6 minutes per side until golden brown and cooked through (internal temperature 165°F).

Let the chicken rest for 5 minutes to retain its juices, then slice into strips.

While the chicken rests, combine 1 cup plain Greek yogurt, grated cucumber (with excess water squeezed out), chopped dill, lemon zest, and a pinch of salt in a small bowl. Stir until smooth, then refrigerate briefly to let flavors meld.

Divide the cooked quinoa among four serving bowls.

Top each bowl with sliced chicken, cherry tomato halves, red onion ribbons, sliced Kalamata olives, and crumbled feta cheese.

Add a generous dollop of tzatziki in the center of each bowl. Serve immediately while warm.