Pre-heat oven to 180 C / Gas 4. In the meantime, brush the slices of bread with garlic oil, and place on the rack in the middle of the oven so that they start to toast but not burn, for around 5 minutes.
Prepare the topping by mixing all the other ingredients together - chopped tomatoes, garlic, onion, olives, basil leaves, oregano, olive oil, and salt and pepper to taste. Mix well.
When the bread is warm enough and just started toasting take out of oven, scoop the mixture onto the bread, sprinkle with Parmiggiano Reggiano and put back into the oven. Take the bread out when the shreds of cheese start to fuse together.