In Canada/Ontario, in both cases of permanent and contract employment, is it possible that I request my employer that they pay me my full before-tax salary and I pay the tax at the end of the year myself?
This blog post might also be relevant:
And this question also:
Does your employer have to hold back taxes on your paycheque?
And, in Form T1, it is written that:
Reduction in tax deductions You can ask to have less tax deducted on your income tax and benefit return if you are eligible for deductions or non-refundable tax credits that are not listed on this form (for example, periodic contributions to a registered retirement savings plan (RRSP), child care or employment expenses, charitable donations, and tuition and education amounts carried forward from the previous year). To make this request, fill out Form T1213, Request to Reduce Tax Deductions at Source, to get a letter of authority from your tax services office. Give the letter of authority to your employer or payer. You do not need a letter of authority if your employer deducts RRSP contributions from your salary.
However, it is not explaining if it is possible to request in T1213 changing tax deduction at source to zero
I want my full tax paid to me and I pay the tax at the end of the year myself. I want to pay no tax on a monthly basis and pay all at the end of the year.