Sardeles se Pita (Σαρδέλες) is grilled sardines in bread, a coastal dish rather than a national counter item. The angle is that it sits at the opposite end of the Greek sandwich spectrum from the chiller-case fillings: it is built around a hot, oily, charred fish that is best within minutes of leaving the grill, and the bread exists to carry it and soak the juices, not to dominate. This is fishermen's-table and seaside-taverna food translated into something you can hold, and it depends entirely on the fish being fresh and grilled properly.
The build is short and the grill is the whole event. Fresh sardines are cleaned, salted, and grilled over high heat until the skin blisters and chars and the flesh is just set. Off the grill they are dressed simply, almost always with olive oil and lemon, sometimes oregano. The fish is then laid into a folded pita or split bread, often with the spine and larger bones removed, sometimes left for the eater to deal with. Good execution means very fresh sardines, a hot grill that chars the skin without drying the flesh, and a generous hit of lemon and oil while the fish is still warm so it soaks in. Sloppy execution is tired sardines that taste flatly fishy, a grill too cool to char so the skin goes flabby, overcooking to dry cottony flesh, and no acid to lift the oiliness. Freshness and grill heat are not negotiable here in a way they simply are not for a canned filling.
It shifts mainly with the bread and the dressing. Some versions use a soft folded pita that absorbs the oil and lemon and becomes part of the eating; others use a crusty split roll that stays distinct from the fish. Dressings stay minimal: oil and lemon is standard, oregano common, occasionally a few rings of raw onion or a little chopped tomato. The canned-tuna sandwich covers entirely different ground, cold and mild, and deserves its own article rather than being crowded in here. As itself, Sardeles se Pita is one of the most location-dependent things in this catalog: near the water with fresh fish and a hot grill it is excellent, and it does not survive being made any other way.