Lightly oil a non-stick baking pan or cookie sheet, or line it with parchment. Place the flatbread in the pan. Drizzle with olive oil.
Spread the onions then the tomatoes over the surface. Sprinkle with oregano, sea salt and pepper. Drizzle a little more olive oil over the surface.
Broil for 5 to 7 minutes at about 6 inches / 15-cm from heat source until the bread is lightly browned and the onions and tomatoes slightly charred.
Remove, cool slightly and serve.