Not quite candy but I think it's close enough to count here: Co-op's own brand salt & vinegar kettle crisps. They're so vinegary it hurts. It's wonderful.
Oh man I love salt and vinegar chips so much but I cannot for the life of me find anything that tastes strong enough that doesn’t cost an arm and a leg in Japan.
I will give you a heads up that if you buy vinegar powder (acetic acid, basically) in an attempt to make your own, be very careful. I made salt & vinegar popcorn once, but the seasoning was too loose on the surface of the popcorn and if i breathed in at all while eating I got a hefty dose of burning lungs