You want:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSWorkspace_Class/#//apple_ref/occ/instm/NSWorkspace/openURLs:withAppBundleIdentifier:options:additionalEventParamDescriptor:launchIdentifiers:
to open a certain URL with a certain app.
and
Pardon the ignorance here if there is some (I'm fairly new to OS X
development)... If I registered my app with a special url scheme and then
sent the mailto url to my app, doesn't that just add an unnecessary hop to
the mix? I will already be inside my app clicking the mailto link, so I
just need
