Melt butter in large skillet over medium-low heat. Add onions and salt, and saute for about 5 minutes.
While onions cook, core bell peppers and slice lengthwise into thin strips. Add bell peppers and black pepper to skillet, and turn heat to medium. Saute for 10 minutes, until bell peppers are soft. Toss occasionally
Place Johnsonville Hot Italian sausages in Johnsonville Sizzling Sausage Grill. Close grill, lock, and plug into outlet. Press button to start grill. When sausages are done, grill will automatically turn off
Open grill with silicone tongs and remove sausages. Cut sausages at an angle into 1" pieces
MAKE SANDWICHES: Lay bottom half of Ciabatta rolls on a flat surface. Place 2 slices of provolone on each half, and then top with bell peppers and sausages. Cover with top of half Ciabatta rolls
Serve at room temperature, or toast in toaster oven until golden and cheese melts