In a mixing bowl, combine olive oil, minced garlic, lemon juice, dried oregano, thyme, salt, and black pepper to create a marinade. Coat the sirloin steak with the marinade, cover, and let marinate in the refrigerator for at least 30 minutes.

While the steak marinates, mix Greek yogurt with grated cucumber, a pinch of salt, and optional honey in another bowl for tzatziki. Cover and refrigerate for at least 15 minutes.

Whisk together vinaigrette ingredients in another bowl.

Heat a skillet over medium-high heat and sear the marinated sirloin steak for 4-5 minutes on each side until reaching an internal temperature of 130°F for medium-rare. Remove and let rest for 5 minutes.

Thinly slice the steak against the grain.

In a bowl, layer cooked grains as the base, followed by sliced steak, cherry tomatoes, cucumber, red onion, and Kalamata olives. Sprinkle with fresh herbs.

Finish with a swirl of tzatziki and drizzle of vinaigrette.