In a bowl, combine the sliced chicken, olive oil, minced garlic, oregano, smoked paprika, salt, and pepper. Mix well to coat the chicken and let it marinate for at least 30 minutes in the refrigerator.
In a saucepan, bring the vegetable broth to a boil. Add the rinsed quinoa, reduce the heat, cover, and simmer for about 15 minutes or until all the liquid is absorbed. Fluff the quinoa with a fork and set aside.
In a large skillet over medium-high heat, add the marinated chicken strips. Cook for 6-8 minutes, stirring occasionally, until the chicken is cooked through and has a nice golden color.
While the chicken is cooking, chop the cherry tomatoes, cucumber, and red onion.
In serving bowls, start with a base of quinoa, add the cooked chicken strips, and top with the diced cucumber, halved cherry tomatoes, sliced red onion, crumbled feta, and chopped parsley.
Drizzle the bowl with lemon juice and a generous amount of tzatziki sauce. Sprinkle lemon zest for an extra burst of flavor.