Place pesto in an air-tight jar or container and cover surface of pesto with a small piece of plastic wrap. Store in refrigerator. Good for about 1 week. Can also freeze excess in ice cube tray. When frozen transfer to freezer safe container.
For the salad:
Bring water to a boil, salt and cook tortellini according to package instructions, about 3 minutes. Drain pasta and transfer to a serving bowl. Drizzle olive oil over pasta and toss to coat.
Cut tomatoes in half and set in bowl. Slice olives and celery stalks, set aside.
Slice Medium Provolone into four ½-inch long strips, then dice strips to make ½-inch cubes.
Add tomatoes, olives, celery, cheese to the pasta. Add the pesto and toss until everything is coated and mixed thoroughly. Serve at room temperature.