I suspect my right rear wheel cylinder is blown. How is the drum removed? Is there a trick?

should just pull right off

Nothing up my sleeve. Jack up rear of car, remove the wheel, release the emergency brake, remove the drum. But if it is stuck(like I think you're suggesting) it might be caused by rust build up around the hub. You might try using emory cloth and maybe some penetrating oil around that portion of the hub and then try to pull off the drum.

My boyfriend is hosing the drum down with Liquid Wrench, now. Still no movement. Any suggestions on using a puller? Slide Hammer?

All help is appreciated.

take a rubber mallet and tap around the edges of it

I believe there'* an access hole in the back plate that you could insert a brake adusting tool to back off the brake shoes. Aside from that I'm not sure what to tell you that might cause damage. Hitting the drum with a heavy hammer could damage the rear bearing. Using a big screw driver to pry it off may bend the back plate. If you have to use a puller, I think you may have a bigger issue(and cause bigger damage).

There'* no access hole on these, My dad was counting on that when he taught me drum brakes We ended up tapping the drum around the perimeter towards the center while pulling forward...

Well all I do is kick it with my size 15'*.. and it brakes lose.. maybe try that

had to tap my to get them off but make sure you use a rubber mallet.

I have always used a large hammer and rapped it hard close to the hub (all around the wheel studs, but don't even accidentally brush the wheel studs). Keep going around the hub until it pops. Once it pops loose you may have to keep turning the drum back and forth while pulling out on it to get it off.