Your unused tuition amounts can only lower your tax owing, not make a refund on their own. You should enter the unused amounts each year, even if you don't use them that year.
So, in your case, your income is quite low meaning you'll likely not need any to reduce your tax owing to zero. Therefore, all of your tuition credits will be carried forward. Tuition credits don't expire so if you return to Canada in the future, those credits will be there waiting for you to claim.