Bring a large pot of water to a boil and cook the orzo according to the package directions.
Meanwhile, heat up a tablespoon of the olive oil in a skillet. Sauté the pine nuts until they're slightly brown; set aside. (You can also just put a single layer of pine nuts on a cookie sheet and pop it in the oven, but I tend to burn them that way.).
I like the tomatoes and mozzarella balls cut in half to increase my chance of getting one or the other in each mouthful, but if you're pressed for time, just dump them into a large bowl with a glug of olive oil, the vinegar, and the bocconcini marinade. Add the basil and the reserved pine nuts.
Drain and rinse the pasta in cold water. Shake as much water from the pasta as you can.
Stir the pasta into the tomato-mozzarella mixture and mix well.
Check the seasoning and add more olive oil, vinegar, salt, and/or pepper if needed. Serve.