much like the whole view (when expressed occasionally by supposed "expert" programmers) that program code is itself like some sort of black-art written off by mages somewhere... seriously?!...

woah mages. That is some serious rank.

Coding down to the metal means usually low level programming.

However when used in conjunction with a job advert like this. It usually means that a recruiter is trying to fill the ad with as many buzz words and phrases as possible. Can normally be read in in Job descriptions that start with "Rock Star Programmer needed".