When Apple first introduced the native, it had neglected to bring the same user-friendly shortcut to OS X. Sure, to get to the emoji keyboard and enter special characters, but it wasn't a button (or in this case, a keyboard shortcut away).
The tip comes from Steve Streza via a tweet:
Mavericks pro tip: Press Command-Control-Space to bring up the new ( emoji panel (! pic.twitter.com/5O0yz0Zr1d— Spooky Streza (@SteveStreza) October 22, 2013
As you can see, it's a simple enough key combination. Whenever you're in a text field on OS X Mavericks, you can press Control-Command-space bar and an emoji picker will be displayed. You can leave it attached to the text field, or drag it away. Leaving it attached will let you pick one emoji and it will close on its own. Dragging it away from the text field will leave it open, allowing you to place several emoji in the text field.
Now that you know how to use emoji on your Mac, what are you waiting for? Ham it up!