See final page of this PDF for cleaning instructions.
1) Maybe... Some people rarely/never clean a centerfire suppressor. Probably some personal preference on when and if to clean. Some people weigh their suppressor and track how much heavier it gets. If you're going to put 22LR through it, you will probably need/want to clean it.
2) Doesn't look like it's "supposed" to come apart (soak and then drain to clean)