Cook the Pasta
Bring a large pot of generously salted water to a rolling boil. The water should taste like seawater.
Add fusilli pasta and cook according to package directions until al dente, about 10-12 minutes.
Drain pasta well in a colander without rinsing. Transfer to a large mixing bowl and let cool slightly.
Prepare the Italian Dressing
While pasta cooks, combine olive oil, red wine vinegar, and pepperoncini brine in a medium bowl. Whisk until emulsified.
Add minced shallots, garlic, dried oregano, dried parsley, salt, and black pepper. Whisk vigorously for 30 seconds.
Set dressing aside at room temperature to let herbs bloom for at least 10 minutes.
Prep Vegetables and Cheese
Drain and rinse chickpeas thoroughly.
Halve cherry tomatoes. Thinly slice mini sweet peppers into rings.
Slice pepperoncini peppers. Halve kalamata olives if whole.
Grate Parmesan cheese. Cube provolone or mozzarella into small, bite-sized pieces.
Roughly chop baby spinach into smaller pieces.
Combine and Chill
Add all prepared vegetables, chickpeas, olives, both cheeses, and chopped spinach to the bowl with pasta.
Give dressing a final whisk, then pour over pasta mixture.
Toss thoroughly using two large spoons or salad tongs until everything is well-coated with dressing.
Taste and adjust seasonings as needed (add more salt, pepper, or vinegar to preference).
Cover tightly with plastic wrap or transfer to an airtight container.
Refrigerate for at least 1-2 hours before serving to allow flavors to meld.