01 - Set a grill to medium-high heat and allow it to come to temperature.
02 - Brush the halved tomatoes, sliced onion, and sliced bell pepper with 1 tablespoon of olive oil, coating evenly.
03 - Place sausages and oiled vegetables on the grill. Cook sausages for 10 to 12 minutes, turning occasionally, until charred and cooked through. Grill vegetables for 4 to 6 minutes until softened with light charring.
04 - Remove vegetables from the grill and let cool briefly. Coarsely chop them into bite-sized pieces.
05 - Heat the remaining 1 tablespoon of olive oil in a skillet over medium heat. Add minced garlic and sauté for 1 minute. Add the chopped grilled vegetables, salt, black pepper, dried oregano, and crushed red pepper flakes. Cook for 3 to 4 minutes, stirring frequently, until the flavors meld. Fold in the fresh basil and parsley.
06 - Split each grinder roll lengthwise without cutting all the way through. Place cut-side down on the grill for 1 to 2 minutes until lightly crisp.
07 - Place one grilled sausage into each toasted roll. Spoon the grilled tomato sauce generously over each sausage. Top with shredded cheese if desired.
08 - Return assembled grinders to the grill over indirect heat, cover, and cook for 1 to 2 minutes until the cheese melts. Serve immediately, garnished with extra basil leaves if desired.