Add the vinegar, Dijon mustard, oregano, Italian seasoning, sugar, olive oil, mayonnaise, salt, and pepper to a jar with a lid.
Shake vigorously until the dressing is smooth and fully combined. Refrigerate while preparing the salad.
Bring 12 cups of water to a rolling boil.
Add 1 tablespoon salt and the pasta.
Cook according to package directions until al dente.
Drain and rinse under cold water for about 20 seconds.
Shake off excess water and allow the pasta to cool.
Chop the chicken, beef salami, tomatoes, olives, roasted red pepper, cucumber, parsley, and red onion.
Add the cooled pasta, chicken, beef salami, vegetables, parsley, and Parmesan cheese to a large mixing bowl.
Pour the dressing over the salad and toss well to coat evenly.
Taste and adjust seasoning if needed.
Cover and refrigerate for at least 10 minutes before serving.
Toss again and serve chilled. This Italian Pasta Salad Recipe is best enjoyed fresh.