Preheat oven to 375 degrees. Line a baking pan with aluminum foil and spray with nonstick cooking spray. Set aside.
In a medium bowl, combine ground pork, Greek seasoning, mint, olive oil, milk and egg. Mix well, and place by spoonfuls onto prepared baking sheet.
Using a fork, flatten into oval shapes, leaving ridges with the fork. Place in preheated oven and bake for 20-25 minutes. Switch to the broiler and brown the meat for 3-5 minutes, or just until the ridges on the meat become darker and crispy. Remove from oven.
Meanwhile, combine the yogurt, grated cucumber, dill, and oregano in a bowl. Salt and pepper to taste. Cover and refrigerate until ready to serve. The sauce will become a bit thinner as it sits due to the water content of the cucumber. This is fine, as it makes it a good consistency for drizzling over the salad.
To serve, pile lettuce, tomato, cucumber, red onion, and crumbled feta on plates. Top with the gyro meat and tzatziki sauce. Serve with warmed pita wedges, and marvel at the flavor of take-out in your own home!