Cooking the chicken: Heat oil over medium-low heat. Stir in the onion and cook until they start to become translucent. Stir in garlic and pepper flakes, cook stirring for half a minute. Add bell pepper, tomato and chicken. Stir to mix. Pour in tomato sauce and stir to mix. Cover and simmer until the liquid has evaporated. Set aside.
To serve.
Cutting cheese: Using a cookie cutter, cut the cheese into 12 small circles (about the size of the crackers), if you don't have a cookie cutter just cut the cheese into squares.
Serving: Arrange chicken, cheese, crackers, parsley and sour cream on a tray. Right before eating assemble by placing cheese on a cracker, topping with chicken, followed by a small dollop of sour cream and sprinkle with parsley. The cheese will prevent the cracker from becoming soggy with the chicken juices, but is best not to pre-assemble.