Usually when you apply for VISA for other countries, in the event of a rejection they do advise on re-apply or appeal. They also state if you are not in a position to appeal .
From what I have read on this form, the CIC does not include any such clause/advise, so you are free to apply at any time. Its only that, you have to mention the previous reason, cause, justify how you are better off now, else you may face rejection again. Please try and ensure that there are no massively contardicting information like NOC, employers etc. It will reflect badly on you.
Cheers