Place the chicken in the freezer for 20-30 minutes beforehand.
Mix all ingredients for the garlic aioli in a medium-sized bowl. Cover, and set in the refrigerator until you’re ready to assemble the sandwiches.
Slice the semi-frozen chicken as thin as possible. Also slice the bell peppers and yellow onion. In a large skillet over medium-high heat, sauté the bell peppers and onion until slightly softened with olive oil. Then add the chicken along with the blackening seasoning and continue to sauté until the chicken is fully cooked.
Smear the inside of each hoagie roll with desired amount of garlic aioli. Top each hoagie roll with two slices of cheese and place them on a baking sheet. Bake for 5 minutes at 400F, or until the cheese has melted and the rolls are slightly toasty.
Fill each hoagie roll with desired amount of chicken cheesesteak filling. Serve immediately with optional pepperoncinis and dill pickles.