Heat a heavy pan with 3 tbsp of oil.
Season the roast with the salt and pepper.
Sear the meat in the pan. When the meat is nice and brown, add the garlic and onions. Continue to cook until the vegetables brown slightly.
Deglaze the pan with the red wine and reduce until almost gone.
Add the tomatoes and stir together.
Transfer the meat and tomato mixture to an Instant Pot and cook for 45 minutes on high, until meat is tender. *
While meat is cooking, combine mayonnaise and garlic powder in a small bowl to make aioli. Set aside.
When meat is tender, slightly break up and adjust seasoning.
Place the meat onto the focaccia bottom buns and add a little of the tomato sauce.
Toss the arugula with the banana peppers and 1 tbsp of olive oil.
Add a splash of the pepper brine and now put on top of the meat.
Smear a liberal amount of aioli on the lid of the bun and then place on top.
*Without an Instant Pot, cover heavy pan with a lid and cook on low for about 1.5 hours, until meat is tender.