It is quite simple...1 proven method I will refer you to, it the type of kishka you have is kaszanka...
Cut the kishka into slices, (fairly large ones, about half inch-inch) Do NOT take off the skin yet.
Put some butter on the pan, enough so that it covers it all. Depends how much kishka you have i guess.
Add pepper and salt for taste while it is frying.
Once it has a nice golden brown colour, and the skin itself is coming off without much help, then it is time to take it off entirely. I find it is easier to take the skin off while it is still on the pan.
Take off skin from each piece. Once you have just the inside of the kishka on the pan, keep frying until you see that it is bunching together a bit, and blackened from bottom (only a little bit). Keep stirring it.
Serve it like that, with a good, fresh, warm piece of bread...
it is something to die for!