In a large mixing bowl, combine ground beef, hot Italian ground sausage, panko, onions, garlic, Italian seasoning, sea salt and freshly ground black pepper; mix well. Divide meat into 4 equal portions and form patties. Place them in a plate, cover with plastic wrap and chill for 2 hours.
Later on, take meat out and let it rest on the counter while making the slaw. In a small bowl, combine tomato, pepperoncini, basil, oil, vinegar, sea salt and freshly ground black pepper; stir well and set aside.
Fire up the BBQ and place patties when the grill reaches high temperature. Close the lid and cook about 5 to 6 minutes per side, flipping once. About 2 to 3 minutes before cooking is done, place hamburger buns on the top grill as well as a couple slices of cheese per patty.
Just before serving, scoop a good amount of tomato slaw on top of the meat. Makes 4 burgers.