Unlock the emoji (japanese variant) keyboard. This is the one I used:
http://itunes.apple.com/us/app/emoji-free/id332509635?mt=8 or search "emoji free" in the app store. It places a globe button in your keyboard so you can easily switch between it and whatever other keyboard(s) you use.
Don't be fooled by the FREE name. All emoji apps unlock the SAME keyboard in iOS with the SAME icons. Don't waste a buck unless you're feeling especially generous or something. The premium versions' authors are ripping people off, IMHO.
Oh, and once you've unlocked the keyboard, you can safely delete the app from your device and maintain full use of the icons.