1/4 cup fresh lemon juice, divided
5 cloves garlic, minced, divided
1 boneless beef sirloin steak (1-1/2 lb.), 1/2 inch thick
1/4 cup chopped fresh dill
2 large cucumbers, peeled, seeded and sliced
1 cup thinly sliced onions
1/4 cup crumbled feta cheese
6 whole wheat pita breads, halved