scrummymummy, my crackling is the stuff of legend and so easy:
don't rub with salt, oil or anything, just roast your meat long and slow, uncovered with water in the bottom of tin.
After it's cooked, you can leave to cool (Which i always do as usually batch cooking on my day off) , and the fat sets on the stock for easy removal.
Anyway, when you come to eat it, lift off the whole piece of skin, easier with just your fingers. Turn over, and using a spoon, scrape away the soft fat from the underside of the skin. Get as much off as you can, leaving just the actual rind.
I then use scissors to cut into strips (easier than snapping later and more even)
You can then then either pop onto a tray for 10-15 minutes in a hot oven, or freeze until needed.
It has always turned out crunchy and sometimes looks like giant pork scratchings!
My kids have taken it to school in thir packed lunch the next day as it's not greasy at all. The school cook asked how I'd made it. :)