Drain pepperoncini's, reserving liquid. Remove and discard stems of peppers, set peppers aside. Cut roast into large chunks; place a third of the meat in a 5 qt. slow cooker. Add water.
In a small bowl, combine the basil, garlic powder, oregano, salt and pepper. Sprinkle half the mixture over the beef in the crockpot. Layer with half the remaining meat, the onions, reserved peppers and the pepper liquid. Top with remaining meat and herb mixture.
Cover and cook on low for 8-9 hours or high for 4-6 hours or until meat is tender. Shred beef with two forks. Using a slotted spoon or tongs, serve beef and peppers on toasted buns!
I don't think this recipe needs cheese, but it would be very good with melted provolone or Mozzarella on top.