In a large skillet over medium heat, add the diced onion and red bell pepper. Sauté for about 3-4 minutes until softened.
Add the minced garlic and cook for an additional 1 minute, stirring frequently.
Increase the heat to medium-high and add the ground chicken to the skillet. Cook until browned and cooked through, about 5-7 minutes.
Stir in the Cajun seasoning, tomato paste, chicken broth, and Worcestershire sauce. Mix well to combine.
Bring the mixture to a simmer and let it cook for about 10-15 minutes until the sauce thickens, stirring occasionally.
Season the filling with salt and pepper to taste.
While the chicken mixture is simmering, lightly toast the sandwich rolls if desired.
Once the filling is ready, spoon the Cajun spiced chicken mixture onto the toasted sandwich rolls.
Serve with sliced pickles and a sprinkle of chopped green onions on top, if desired.