To a measuring cup or medium bowl, add olive oil, red wine vinegar, lemon juice, sugar, garlic, Dijon mustard, oregano, kosher salt, and pepper. Use an immersion blender and mix thoroughly.
To a large salad bowl, layer the ingredients in the order listed: chopped lettuce, halved cherry tomatoes, diced green bell peppers, diced cucumbers, cubed mozzarella, sliced salami, sliced onions, sliced olives, sliced banana peppers, chopped basil, and chopped parsley.
Topping the salad with the zesty dressing and serve.
Notes
Keep leftover salad in an airtight container in the refrigerator for 4 days.