In a small bowl, mix together olive oil, minced garlic, lemon juice, dried oregano, dried thyme, salt, and pepper. Coat the sirloin steak with this marinade, ensuring it’s evenly covered. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes but up to 4 hours for deeper flavor infusion.

In a medium bowl, combine Greek yogurt, minced garlic, grated cucumber, honey, and fresh dill. Stir everything together until it's smooth and well-blended. For the best flavor, cover the tzatziki and chill in the refrigerator for at least 20 minutes.

Heat a large skillet over medium-high heat. Once hot, add the marinated steak and sear it for about 4-5 minutes on each side until it reaches your desired doneness, ideally medium-rare to medium. Transfer to a cutting board and let it rest for at least 5 minutes before slicing thinly against the grain.

Prepare serving bowls with a base of cooked grains like brown rice or quinoa. Top with sliced steak, halved cherry tomatoes, diced cucumber, thinly sliced red onion, Kalamata olives, crumbled feta cheese, and fresh herbs. Drizzle with tzatziki sauce for a complete experience.