Cook the chicken: Use pre-cooked rotisserie or poach chicken breasts in salted water until done, then chop or shred. Let it cool slightly.
Make the dressing: In a bowl, whisk yogurt, olive oil, red wine vinegar, Dijon, garlic, oregano, Italian seasoning, red pepper flakes, salt, and pepper.
Adjust vinegar and salt to taste.
Prep the veggies: Shred romaine. Slice onions thin so they don’t overpower. Dice cucumber and halve tomatoes.
Slice pepperoncini and roasted red peppers.
Toss the chicken: Mix the chicken with 2–3 tablespoons of the dressing so it soaks up flavor.
Build the salad: In a large bowl, add romaine, tomatoes, cucumber, onion, roasted red peppers, pepperoncini, olives, and parsley.
Add protein and cheese: Fold in the dressed chicken. Add provolone or Parmesan if using.
Dress and serve: Drizzle on more dressing and toss until lightly coated. Taste and adjust salt, pepper, or vinegar.
Serve right away.