Add all dressing ingredients to a small jar with a tight-fitting lid. Shake to to mix. Taste and more pepperoncini brine and or sugar to taste.
Salad
In a 12-inch skillet, heat 2 tablespoons of olive oil. Add pepperoni (2 ounces) and cook, over medium heat, stirring often, until pepperoni is crisp. Transfer to a paper towel-lined plate, and cool.
In a large bowl, combine romaine (1 large head), pepperoncini (3 tablespoons), grape tomatoes (1 1/2 cups), red onion (1/4 cup), black olives (1/2 cup), mozzarella (1 cup), and garbanzo beans (1 cup). Add dressing to taste and toss until evenly combined.
Divide salad among plates and top with grated parmesan (1/4 cup) and julienned basil (1/4 cup).