To recursively set prop for pool/fs/root and descendants with the exception of a few (eg mountpoint) non-inherited props:
zfs set prop=val pool/fs/root

Recursively reset (restore prop to inherited (if set "higher" in the tree) or default otherwise, or remove (if a user prop)):
zfs inherit -r prop pool/fs/root
//

You can delete a user property (those with a colon, e.g. com.sun:auto-snapshot:yearly) with the zfs inherit command, e.g
zfs inherit com.sun:auto-snapshot:yearly <dataset>

From RTFM zfs(8): Use the "zfs inherit" command to clear a user property. If the property is not defined in any parent dataset, it is removed entirely. Property values are limited to 1024 characters. //

Inheriting nonexistance, thats fun. I think a parent should be able to force behavior on its lineage, as well as trusting the child to imitate its behavior. Maybe the developers are training us to be better parents.