Here is the complete tutorial on how to become a fire ninja:
Once your earn all your belts and your ninja mask, head over to the ninja hideout and buy the amulet to play this member only game. Sensei will give you a starter deck and the complete guide on how to play. The Fire Suit consists of the fire sandals, the fire suit, the fire mask, and the firy helmet.
Once you earn your fire ninja outfit, challenge sensei for the legendary fire gem which will be placed on your amulet if you win. Once you complete your fire suit it should look like this.
Have you noticed that the whole ourfit has a special dance and wave? Try it out for yourself! There is also a super-secret that few penguins know about. That if you are in your fire suit, you go to the cove, you get many penguins to sit about the fire, and then you stand in front of it and do the dance, the fire will grow!
(Credit to ECCP http://elitecheaters.wordpress.com/)