If you haven't already, cut leeks in half and then in half moon shapes. This will help get all the dirt out in between the layers. Wash in a bowl full of cold water and then remove the leeks.
In a separate pot, boil leeks for about 5 minutes until they begin to soften. Drain and dry very well.
In a wide and deep skillet, heat oil to about 350 degrees or until oil sizzles when something is dropped in. Oil should be about ¼-1/2in deep.
In a clean bowl, add the chopped sirloin, leeks, 1 beaten egg, salt and pepper. Mix until well incorporated.
Create a dredging station, 1 bowl with flour and 1 bowl with the remaining 2 eggs
Form the mixture into patties about the size of a small palm-size. Dredge in flour, egg, flour. (It will be messy).
Then pan fry in oil until golden brown on each side, 3-5 minutes.
When keftikas are done, place on paper-towel lined plates and sprinkle with kosher salt.