Italian Sub Pasta Salad

• ½ red onion, thinly sliced
• ice water, for soaking onion

Dressing

• ¼ cup red wine vinegar (60 mL), plus more for serving
• 3 tablespoons mayonnaise
• 1 tablespoon spicy mustard
• 2 teaspoons dried oregano, crushed
• kosher salt, to taste
• freshly ground black pepper, to taste
• ¼ cup good-quality extra-virgin olive oil (60 mL), plus more as needed

Salad

• 8 oz pasta of choice (225 g), cooked al dente, drained, and cooled
• 4 oz sliced coppa (105 g), sliced
• 4 oz sliced prosciutto (105 g)
• 4 oz sliced good-quality mortadella (105 g)
• 4 oz thinly sliced Provolone cheese (105 g)
• 4 oz thinly sliced fresh mozzarella cheese (105 g), seasoned lightly with salt
• 1 pt cherry tomatoes (473 g), halved and seasoned lightly with salt
• ½ cup giardiniera (70 g), thinly sliced
• ⅓ cup pickled pepperoncinis (50 g), thinly sliced
• ½ head iceberg lettuce, thinly sliced
• torn fresh basil leaf, to taste
• Crushed salt and vinegar potato chip, (optional), for garnish