In a medium bowl, whisk together olive oil, lemon juice, honey, minced garlic, and dried oregano to create your zesty marinade. Submerge the sirloin steak in the mixture, cover, and refrigerate for at least 30 minutes.

In another bowl, combine Greek yogurt, grated cucumber, lemon juice, minced garlic, chopped dill, salt, and pepper to prepare tzatziki. Chill in the refrigerator.

Heat a skillet over medium-high heat and sear the marinated steak for 4-5 minutes on each side or until desired doneness. Let the steak rest for 5 minutes.

Layer cooked quinoa or bulgur in serving bowls. Slice rested steak and arrange on top. Add cherry tomatoes, diced cucumber, red onion, and kalamata olives.

Sprinkle feta cheese on top if desired. Garnish with fresh herbs and drizzle tzatziki sauce and vinaigrette over the bowl before serving.