01 - Preheat oven to 350°F (180°C).
02 - Lightly brush each barley rusk with olive oil using a pastry brush. Arrange on a baking tray and bake for 5 to 8 minutes until golden, crisp, and fragrant.
03 - While the rusks toast, combine the finely diced tomatoes, half of the chopped oregano, and a pinch of freshly ground black pepper in a mixing bowl. Toss gently to combine.
04 - Remove the rusks from the oven and let them cool slightly on the tray for 2 to 3 minutes.
05 - Spoon the tomato mixture evenly over each rusk. Crumble feta cheese generously on top of each piece.
06 - Scatter red onion slices, Kalamata olives, capers if using, and the remaining fresh oregano over the assembled rusks.
07 - Drizzle with additional extra virgin olive oil and finish with a generous sprinkle of freshly ground black pepper. Serve immediately while the rusks are still crisp.