I didn't just do that...
 

Went to the beach with my Canon XH-A1 today. When I got back I found some sand on it here and there so I brought out my trusty canned air and blew it all off. Totally absent minded, I opened the cassette compartment and blew a few seconds of air in there...

Did I just screw my camera (heads, inside)...?

Everything seems to be working fine, but I was just worried I may have hurt something.

Anyone do this before or is this actually a good procedure to do...?

Was there sand around the cassette compartment? Did it get wet at all?
If you're worrried about it, maybe look at sending it into Canon to be thoroughly cleaned.

I learned the following from a dark moment in my photographic history in which I got nailed by a sizable wave in Oxnard about 20 years ago. Unfortunately I had my Nikon F2 and a couple lenses with me....the camera lasted another 4 years.

You can usually clean minor amounts of sand out, by having a shop do it for you.
The real threat to going to the beach comes from the possibility of salt water corrosion, if it gets wet. There is no fix for that.

I think it depends on how you did the blowing. If you opened the cassette compartment, pointed the tube into the opening and let it rip, that could be bad. If you used a delicate touch, you're probably alright.

Remember that those cans of compressed air can expel its contents in a very cold, liquid form if you're not careful in following the directions. That might be the biggest peril in doing what you did.

It was just two good squirts of air, no liquid. I just thought it may have blown some lubricant off the reading heads or something.

Back in my Betacam days I shot in lots of dirty environments and always used canned air carefully inside the tape compartment. I'd do that, then clean the heads themselves. I doubt you caused any problem. I wouldn't do it as a normal procedure.