What type of training is required to get the best out of mellenials?

1 rule, aquire skills that no other have. Most of the times, companies are looking forward for people that are team players, experts and accepts challenges. 

To me, I think you should give them the very training they savvy for-Technology based. However, it depends on the work environment and nature of the job to be done. Again it could also depend on your knowledge of generational identity. Somebody like me,born on 1988, I am internet savvy, though not lazy but I can do without internet even if it means manual labour so long as I get paid of the job well done!