To get PCC from KSA more complicated than other countries, anyway, here is the process :
You will be sent an introduction letter "request letter" from the Canadian high commission in london for the saudi police clearence certificate. You will have to provide your country PCC and you will be required to provide a PCC for all those countries where you have been more than a period of 6 months .
When Canadian High Commission in London sends you a letter of Introduction , then go to Canadian Embassy, Riyadh with this letter then they will provide you with their request addressed to the ministry of foreign affairs saudia , then you will have to go to the ministry office and then you will be asked to show your Iqama and passport it takes approximately 7 to 15 days from them to provide another form with addressed to the CID office for your area, then when you go to the CID office you will be asked to provide your passport and Iqama, you will have to do fingerprint and retina test (if it is not done before) and then finally, approximately after 7 days you will be handed your PCC, but the time what I mentioned above is never approximate as in this country every thing depends on their moods
Regards