Preheat oven to 180°C.
Season veal with salt and pepper. Heat a quarter of the olive oil in a large frying pan over high heat. Add veal and cook, turning, until browned all over.
Transfer veal to an oven tray and roast until medium-rare, or when it reaches an internal temperature of 55°C (15 minutes). Remove pan from oven (leave oven on, and reserve any juices) and place veal on a wire rack to cool. Slice thinly and set aside.
Drain tuna (reserving water) and place in a food processor with the extra-virgin olive oil, anchovy, capers, lemon juice and pan juices. Process until creamy then combine with mayonnaise. If the mixture is too thick, stir in some of the reserved tuna water. Season with cayenne. Just before serving, fold in parsley.
Cut 18 slices of ciabatta and place on a baking tray. Use a pastry brush to paint bread on both sides with remaining olive oil. Bake in oven until just starting to turn golden. Rub both sides of the croutes with garlic then bake for a further 8 minutes, or until crisp and golden.
Spread tuna mix on each ciabatta croute. Top with veal slices then garnish with lemon zest, caperberries, a drizzle of extra-virgin olive oil and balsamic. Sprinkle with fresh thyme leaves and serve.