Roast Pork Sandwich

Ingredients

• For the Brine and Roast Pork Loin
• 2 cups kosher salt, plus more
• 3 bay leaves
• 3 sprigs rosemary
• 3 sprigs thyme
• 1 head garlic, halved crosswise
• 1⁄2 bunch flat-leaf parsley
• 1 (2–3-lb.) boneless pork loin, tied with kitchen twine
• Freshly ground black pepper, to taste
• For the Tonnato (Tuna Mayonnaise) and Serving
• 1 tbsp. plus 1/4 cup red wine vinegar
• 2 egg yolks
• 1 cup canola oil
• 1 1⁄2 tbsp. capers, drained, rinsed, and finely chopped
• 1 1⁄2 tsp. crushed red chile flakes
• 1 1⁄2 tbsp. finely chopped drained anchovy filets in oil
• 5 oz. high--quality jarred tuna in oil, drained and flaked into small pieces
• 1⁄4 cup extra-virgin olive oil
• 1 red onion
• Kosher salt and freshly ground black pepper, to taste
• 6 crusty sandwich rolls
• 4 oz. arugula