Place a small pot of water on the stove to boil. Add a tablespoon of salt. Once boiling, add orzo and cook until al dente (should take between 6-8 minutes; check package directions for exact time). Drain pasta. Add to a large bowl with ⅔ cup of Greek dressing (recipe below). Toss to combine. Let the pasta cool before adding the rest of the ingredients.
Once the pasta has cooled, add in the rest of the pasta salad ingredients. Season with a little salt and pepper, as needed. Serve immediately or within 12 hours. If making ahead, add in the romaine right before serving.
For the Greek dressing:
Add all ingredients to a mason jar. Cover and shake to combine.