Make a quick pickle: slice carrots and red bell pepper (if using) into matchsticks and your peppers into thin rings. Add vinegar, salt, and sugar into a small bowl and stir very well to combine. Add carrots, bell pepper, and pepper rings and toss in the vinegar mixture. Store in the refrigerator for up to a week.
Form meatballs: In a large bowl, add ground pork, crackers, garlic, ginger, diced peppers, cilantro, scallions, lime juice, and fish sauce. Using your hands, combine all of the ingredients into a consistent meat mixture.
Pull off 2 or 3 tablespoons of the meat and roll it into balls with about a 2-inch diameter. This is all easiest done with your hands. Add the balls to a sheet tray or baking dish. Continue shaping meatballs until you've used all the meat.
Preheat the oven to 425 degrees F (218 C).
Bake meatballs for 18 to 20 minutes.
Start the sauce: After the meatballs have been in the oven for 5 minutes, add 1 tablespoon of olive oil to a large skillet. Once the olive oil is shimmering add 3 tablespoons of green curry paste. Cook for 2 minutes stirring occasionally.
Add the can of coconut milk to the pan with the green curry paste. Cook the sauce at a low simmer for 10 minutes or until the meatballs are done.
When the meatballs have been in the oven for 18 to 20 minutes, remove them and add each meatball one by one into the simmering sauce.
Cook sauce with the meatballs for another five minutes or until the sauce has thickened.
Make the sandwich: slice a French bread roll halfway through and open it up like a book. If the roll gives resistance and feels like it might break in half, toast it briefly first and it will soften up.
Add one or two spoonfuls of sauce to the inside of the bread roll. This moistening step is crucial for making the sandwich juicy and flavorful.
Select 3 or 4 meatballs and snuggle them inside the split bread roll. Add more sauce if desired.
Add several of your quick pickled carrots and peppers. Add cilantro leaves as garnish if desired.
Serve the sandwich and enjoy.