In a small jar or bowl, whisk together the olive oil, red wine vinegar, dried oregano, garlic powder, salt, and black pepper until emulsified.
Wash, dry, and chop the Romaine lettuce and place in a large salad bowl.
Add the halved cherry tomatoes, sliced cucumbers, red onion, and black olives to the bowl.
Drizzle the prepared vinaigrette over the vegetables and toss gently to coat.
Top the salad with pepperoncini peppers, grated Parmesan cheese, and croutons immediately before serving.