In North American English they're 'pickles'. In Britain, Ireland, Australia and so on, they're 'gherkins'. In many European languages (including German, Dutch, Swedish, Danish, Norwegian, Russian, Estonian, Finnish) they are simply "pickled cucumbers". Or they use an term unrelated to pickling like French cornichons (small horns) or Spanish pepinillo. (diminutive for cucumber)

So asserting that cucumbers are the most popular pickled vegetable in the entire West based on the American English term is quite a leap to conclusions.