Cut the fish into small julienne pieces and keep them in a bowl.
Now, add 1 tsp white vinegar, ½ tsp of red chili flakes, 1/3 tsp regular table salt, a pinch of Kashmiri red chili powder, and 1 tsp of coriander and cumin powder mix. Follow it with 1 tbsp of refined wheat flour (maida), and half of one whipped egg to it.
Mix everything nicely and keep it aside for about 5 to 10 minutes to set properly.
In the meantime, take a frying pan or kadai and heat an adequate amount of cooking oil in it on a high flame. Turn the flame to medium when the oil heats up put the fish pieces one by one in it.
Fry them until they turn golden brown and become crispy. Take them out and put them aside on a plate. (Pro tip: Do not fry the fish pieces on a high flame. It will cook the outside quickly while the inside will remain uncooked. And, since you will put the pieces one by one, the pieces put at first will burn by the time the others get cooked nicely).
Now, make the salad. Take ½ of a medium-sized tomato, ½ of a medium-sized onion, and 2 large pieces of cabbage leaves (fresh or parboiled), and chop them finely. Mix them.
Now, to make the pockets, take 2 slices of bread and place a small bowl of about the same size on the top center of them as shown.
Now, press the bowl hard to cut it. (Pro tip: This is the easiest and quickest way to cut the bread slices and join the edge at the same time).
Press it again to flatten and join the edge nicely.
Fry it on a low flame.
Take it out when it becomes crispy and golden brown in color. See that it is perfectly swollen again. Repeat steps 7 to 11 to make all bread pockets.
Now, take one bread pocket, and cut it into half to get two bread pockets.
Fill each bread pocket first with one or two pieces of fish. Then, fill it with a little bit of salad.
Put some mayonnaise and barbecue sauce on top. (Pro tip: If you do not have mayonnaise and barbecue sauce, you can add any type of sauce to the bread pockets such as chili sauce, tomato sauce, and others, Make a combination for an enhanced visual appeal).
Fill all the bread pockets in the same way. Now serve them hot on a plate, with or without any additional condiment.