Put the basil, pine nuts, garlic, cheese, and salt in a food processor. Pulse until well chopped and then drizzle in the olive oil while the machine is running. Continue processing until smooth.
Lay the flat breads on a baking sheet. Divide the pesto mixture between the two flat breads. Top with the tomatoes and cheese, and broil until cheese is melted and lightly browned, about 4-5 minutes. Slice into wedges and serve.