To me a steak gyro is sort of a greek fajita featuring the flavors of the mediterranean. For these gyro's, the steak is marinated, served on a warm pita, then drizzled with a cool cucumber-dill yogurt sauce. The steak is best if it's placed into the marinade several hours before you plan to prepare the gyros. The tzatziki sauce also needs to be prepared in advance to allow the flavors to come together. Take time to marinate the steak and make the tzatziki sauce earlier in the day, and you'll have a flavorful meal ready to serve in less than 20 minutes.