6 ounces crumbled feta cheese
2 teaspoons minced fresh oregano
2 teaspoons fresh rosemary
3/4 teaspoon freshly ground black pepper, divided
1 tablespoon finely grated lemon zest
1 1/2 pounds ground lamb or beef
1/2 cup kalamata olives, pitted and chopped
1 tablespoon chopped fresh dill
1 tablespoon chopped fresh parsley
2 tablespoons fresh lemon juice
1/4 teaspoon sugar
4 tablespoons olive oil, divided
4 kaiser or other sandwich rolls
1 large tomato, sliced
1/4 medium English cucumber, thinly sliced
1/2 medium red onion, thinly sliced
8 romaine lettuce leaves