When cucumbers begin to get slimy it's a sign that the cucumbers are going bad and is due to the aging process.
Slimy cucumbers are a common trait of bad cucumbers and means they should not be eaten.
Cucumbers also become wrinkled and develop soft spots as well as them getting slimy feeling.
A good way to tell that cucumbers are going bad is to check if they become mushy and develop a white slimy feeling.
If they have throw the cucumbers out and do not eat them because they could make you sick and they certainly won't taste very good.