They are pickles you set in the sun to ferment. Here's the recipe we use:

Hungarian Sun Pickles

Wash medium sized cukes well. Cut off both ends. Boil 1 qt of water w/ 2 TBSP salt. Let cool. Place 2 heads of fresh dill and 2 cloves of garlic on bottom of wide mouth glass jar. Arrange prepared cukes in jar, cover w/ sprig of dill and 2 more cloves of garlic. Place on slice of seeded rye bread on top. Pour water solution to cover cukes. Place in sun for 5-8 days to ripen.

Once the pickles are finished, rinse each pickle, slice and put into a jar. Mix the same water solution, as above, letting cool. Mix pickle solution and new water solution, sifting to remove any rye seeds, parsley or garlic. Fill jars with sifted solution.