Boil orzo and water according to the package directions to al dente. This should take 8-9 minutes.
Drain cooked orzo in cold water.
While orzo is cooking mix vinegar, olive oil, and Greek seasoning and set aside.
Dice the rotiesserie chicken into bite-sized pieces
Slice the Kalamata olives, cherry tomatoes, and pepperoncini peppers into bite-sized pieces.
Cut the feta cheese into small cubes
Mix, all ingredients except feta cheese and dressing in a large bowl.
Drizzle dressing over the mixture.
Fold in dressing and feta cheese.
Garnish with pita toast or naan bread and fresh oregano leaves.
Serve at room temperature or cover and refrigerate.