1. In a small bowl combine the cucumber, salt, and lemon juice.  Put in a strainer over top of a bowl and let sit for 30 minutes.

2.  Discard the liquid from the cucumbers, then in a small bowl combine the Greek yogurt, cucumber mixture, garlic, black pepper, dill, and oregano.  Mix well and place in the refrigerator until ready to use.

3.  Cut off the top quarter of each pita.  Tear one of the quarters into 1 inch pieces and place in a food processor.  Add the onion, lemon juice, salt, pepper, oregano, and garlic to the pita in the food processor.  Pule until a smooth paste forms.

4.  Put the onion mixture into a large bowl.  Add the ground lamb and mix until well combined.  Form the ground lamb mixture into 4 or 5 log shaped patties that will fit inside the pitas. 

5.  In a large skillet over medium high heat, heat 1 teaspoon of olive oil.  Add in the ground lamb patties and cook for 4-5 minutes per side.  When the patties are cooked through remove from the pan to a paper towel on a plate.

6.  To assemble put 1/4 cup of Tzatziki sauce in each pita followed by a lamb patty.  Top with lettuce, feta cheese, and red onion.