Place a large baking sheet in the refrigerator to chill. Meanwhile, whisk all the vinaigrette ingredients together in a bowl until well combined. Taste and adjust for seasonings if desired. Set aside.
Bring a large pot of salted water to a boil.
Add the orzo pasta to the boiling water and cook to al dente according to the package directions, about 9 minutes.
Drain the pasta (do not rinse it), and put it back in the empty pot, stirring in 1 tablespoon of olive oil until the pasta is evenly coated.
Take the baking sheet out of the refrigerator and spread the pasta out on the cold baking sheet. Set aside until the pasta is cool, about 10 minutes.
Transfer the pasta to a large mixing bowl, add the remaining pasta salad ingredients, and pour the vinaigrette on top. Toss well.
Serve immediately or refrigerate for up to 4 days. If serving later, bring the pasta salad back up to room temperature before serving.