Combine the ingredients for the dressing in a bowl or jar (olive oil, red wine vinegar, lemon juice, Dijon, garlic powder, Italian seasoning, salt, pepper, sugar, grated Parmesan). Close the jar tightly and shake or whisk in a bowl until the ingredients are incorporated.
Cut or slice any meat or cheeses into bite-sized pieces. Drain the olives and any brined vegetables. Thinly slice the red onion and slice the grape tomatoes in half.
Lay your greens in the bottom of a bowl, then top with your antipasto items. Give the dressing one last whisk or shake, then drizzle over the salad (start with half the dressing and add more as needed). Toss the salad until everything is coated in dressing, then enjoy.