I rent out a residential property. What are some tax implications, with regards to sales tax ?

Rental income is a GST/HST exempt supply. This means that you cannot charge GST/HST on rent.

Furthermore, you may incur expenses in the course of renting out your property on which you may have paid GST/HST, such as management fee, supplies, etc. Normally, you can claim this GST/HST paid on expenses as Input Tax Credits (ITCs), but since rental income is exempt, so you cannot claim ITCs either. Actually, you should not be filing a GST/HST return at all. However for commercial rental property, different rules apply.