To make the salad dressing, whisk together olive oil, lemon juice, sea salt, sumac, red pepper flakes in a small bowl; set aside.
Toast 4 sourdough bread slices after applying some oilve oil in a toaster or in a pan over stove top.
To assemble the salad, place lettuce and rocket leaves in a bowl; top with cucumber, tomatoes, olives, feta cheese, toasted bread squares. Pour dressing on top of the salad and gently toss to combine.
Serve immediately.