Greek Steak Pita with Tzatziki Sauce and Marinated Red Onion

I've been enjoying Greek flavors lately and was craving an easy and healthy yet tasty dinner. I marinated some flank steak, made a cucumber tzatziki sauce and made marinated red onion. I threw it all together in a pita with some lettuce, tomatoes and feta cheese. I served it with hummus and fresh vegetables for a very delicious dinner that we all really enjoyed.Steak Marinade:3 tbsp red wine