I am planning to sell sandwiches and other kinds of refreshments on on a beach that's located on a park next to a downtown urban city . Is this legal for me to be selling refreshments on a beach or do I have to get permits to sell on a beach that's located on a park ? It's going to be like a hotdog stand only smaller . It's on a canadian park .

Permits, inspection of your kitchen by the proper authorities, the "stand" approved.

Generally public parks gain revenue by licensing concessions for food and souvenirs. Usually these concessions have exclusive rights to sell. In addition, the local Health dept requires food vendors to obtain a license.

So you need to contact the local Parks dept and Health dept to see what licensing is required.