In a bowl, whisk together olive oil, paprika, cumin, garlic powder, salt, and pepper. Add the chicken strips and toss to coat. Let marinate for 5–10 minutes while you heat a skillet or grill pan over medium-high heat.
Cook the chicken until it is cooked through and nicely browned on the edges, about 6–8 minutes, turning once. Remove from heat and set aside to rest for a couple of minutes before slicing.
While the chicken cooks, fluff the cooked quinoa and prepare the vegetables: dice the cucumber, halve the cherry tomatoes, and slice the olives.
Make the Greek yogurt sauce: in a small bowl, combine the Greek yogurt, minced garlic, lemon juice, dill, and a pinch of salt and pepper. Stir until smooth and well mixed. If the sauce is too thick, thin with a teaspoon or two of water or extra lemon juice.
Assemble the bowls: divide quinoa among four bowls. Top with chopped cucumber, tomatoes, olives, and feta. Add sliced chicken on top. Finish with a generous dollop of the Greek yogurt sauce and a sprinkle of parsley if using.
Serve immediately, or cover and refrigerate the components separately for up to 2 days. If chilling, keep the yogurt sauce in a separate container and assemble just before eating.