iSSH has a button on the toolbar for exactly this purpose:
Tap that button, view that menu, enable the feature!
I would recommend the following setup (which is what I currently use):
Use Plex as your remote-control-friendly home theatre hub. I find Plex to be much easier to set up than XBMC, but where I think Plex really shines is in how easy it is to share your mini's media with other devices.
On your mini you install both the Plex Media Server and Plex Media Center apps. If you want to stream to additional Macs or PCs, you can install just the Media Center on those.
On your iOS devices, you can install Plex Mobile to stream your mini's media to the device. Plex Mobile can also be used as a remote control for Plex.
You can add your iTunes Media folders to Plex to access your iTunes songs and videos, however neither Plex nor XBMC can play DRM videos purchased from iTunes.
Hulu Desktop is a remote-control-friendly app for browsing and watching Hulu videos. Best of all, you can launch Hulu Desktop directly from Plex.
HippoRemote is a remote control app with better integration with various media players than Mobile Mouse (formerly Air Mouse) and Plex Mobile. Plex Mobile only works with Plex, Mobile Mouse works with most things except Plex. HippoRemote works with Plex, Hulu Desktop, and just about everything else, and it even works with the Netflix player.
HippoRemote also has much smoother mouse tracking than Mobile Mouse.
The Apple Remote is certainly easier to just pick up and use than using than any remote app, so it can be handy to have it close by for quickly navigating Plex and Hulu Desktop on a whim.
I actually don't have one of these yet, but I know several people that love Logitech's Harmony remotes. If want a remote that will also control your TV and receiver, these would definitely be worth checking out.
Best Answer
You can use your Mac as a Bluetooth keyboard for your Apple TV. I.e. type on your Mac's keyboard to have text appear on Apple TV.
For this you need Type2Phone ( http://www.houdah.com/type2Phone/ ) from the Mac App Store.
Full disclosure: I am the developer of Type2Phone.