i m not sure about ur questions .. you dont need to pay US deduction (ss, medicare, payroll ... ) once you move to canada ... now if you are refering to tax return then you can use friends mailing address to get the tax return check ( assuming you won't have US bank account) ...
Sorry you are not getting my question

Every year taxes are deducted, but also social security & medicare is also deducted, social security & medicare is for future.
People who lives in USA get social security & medicare benefits in future, and once I move to Canada, I will never get benefit from those deductions which are being made in last 6 years (social security & medicare).
Is there any treaty or law which allow to move those to Canada?
I am not asking for tax deduction made in past or filing new taxes in future.