Heat the griddle on medium heat to about 350-400°F. Pour the marinara sauce in a small saucepan and set the pan on the griddle. Heat the marinara, stirring occasionally, until it has reduced and thickened.
While the marinara is reducing, place the Italian sausage links on the heated griddle to begin browning. Cook on the first side until nicely browned, then flip and continue to cook until sausage is about 50-60% cooked through. You may need to flip a few additional times for even cooking and browning.
While the sausage is cooking, add about 1 tablespoon of cooking oil to a clear space on the griddle and spread it around with your spatula. Add the sliced bell peppers and onions to the oiled griddle. Sprinkle with the all-purpose seasoning or salt and pepper. Sauté veggies until about 50% done.
When veggies and sausage are about 50-60% done, lay the sausages on top of the vegetables. Continue to cook the sausage and vegetables another 2-3 minutes. Then slowly pour about ½ can of beer, a small amount at a time, evenly on top of sausage and veggies pile. *The beer will create steam, flavoring the sausage and peppers and helping to cook them.
While the sausage and vegetables cook, butter your ciabatta buns and put them cut side down in a clear space on the griddle to toast.
When sausages are fully cooked (165℉ internal temp), transfer to a cutting board to rest and cool a bit.
When veggies are done to your liking, separate into 4 equal thin piles on the griddle, shaping each pile so it's the same size as the bun. Add a tiny amount of beer (about 1 tablespoon) to each veggie pile to create steam. Immediately lay a piece of provolone over each pile of veggies.
Assemble the sandwiches: While cheese is melting, apply thickened marinara sauce to the bottom bun for each sandwich. Slice slightly cooled Italian sausage into medallions on the bias, and then lay the slices directly on the marinara layer. Remove the melted provolone, peppers, and onions mixture from the grill and slide it all on to the sausage. Crown with the other half of the ciabatta bun. Serve immediately.