transphy Dec 18, 2014:

Some text, as to where this is taken out of context from, will be helpful (!!!)

Peter Close Dec 18, 2014:

Although Constantine Kourakis’s, D. Harvatis’s and Andras Mohay’s descriptions or explanations or background information of 'πρέκι' are all correct, I would like to clarify the meaning of the expression ‘σκίζω τα πρέκια’ so that you can select the answer which you consider to have been most helpful.
A 'πρέκι' is a horizontal beam that is placed above a door or window frame to support the wall above the door or window opening.
Therefore, if you “tear down the horizontal beams [that support the wall above a door or window opening”], you will cause that section of wall to collapse, which, in turn, will cause the house owner a lot of bother.
So, the meaning of the phrase is that you 'will cause the person that you are saying it to a lot of bother'.
Yes, this is a slang phrase which is commonly used. It has the advantage of being less vulgar than the word immediately preceding ‘σκίζω τα πρέκια’ in your list.
[If an asker only awards points to an answerer and not to people who provide reference entries, then your selection will be much easier!]