Slice cucumbers into coin shapes and pack them into a quart-sized mason jar.
Add fruit lambic, sugar, and salt to a small saucepan over medium-high heat.
Bring the beer mixture to a boil. As soon as it starts boiling, stir the mixture, remove it from the heat, and pour it into the jar over the cucumbers. This is obviously a hot pot pouring hot liquid so be careful. I typically do the pouring process in the sink so any spilled near-boiling liquid does not hurt anyone.
Close the jar lid and let rest on your counter until cool.
Add to the fridge and enjoy some great lambic pickles over the next few weeks.