For the peperonata, wash and slice the bell peppers into fine strips, cook over a moderate fire in olive oil with the garlic. Sprinkle with the sugar and allow caramelization, pour over some water and set to simmer. Stir in the sun dried tomatoes, capers, olives and sultanas, simmer for 10 minutes, adding water when necessary, when ready the mixture should look have the consistency of thick syrup. Take off from heat, allow cooling and sprinkle with fresh herbs. To serve, rub the bread with the garlic, drizzle with olive oil, grill or bake into crunchy crostini. Grill the tuna to the desired temperature. Spread the bread with a thick layer of Irkotta, top up with the peperonata and slices of the grilled tuna.