Hello, never posted in this topic before but I do regularly make pickled onions, as follows:
I use ordinary Sarsons malt vinegar, adding spices (for a small jar) - 1 dried red chilli, 3 or 4 peppercorns, 1 clove, sprinkle of mustard seeds.
Peel the onions, put in a big bowl and sprinkly very liberally with salt, wnough to give them a good coating when shaken a bit. Cover in cling film.
Next day, peel the film back, tip off the juice, put similar amount of salt on, cover and leave again.
Repeat for 3 or 4 days till not much more j uice comes out (this is what makes them crispy)
Rinse, and rinse and rinse to get all the salt off (not j ust under the tap, submerge them, tip through a colander, repeat 3 or 4 times. I failed to rinse properly once, salty pickled onions, yuck
Sterilise your kilner jars, packs with onions, fill with vingear adding ths spices as you fill. They need to stand for about 6 weeks before eating.
When they're gone, filter the vinegar through kitchen towel and either use it again or have it on chips, yummy.