Assalamu alaykum sister Salam786,
Unfortunately I do not know of a particular dua to say when applying for a job but I guess like anything new we start we should mention and clarify our intentions for the sake of allah swt so it becomes a form of worship inshaAllah.
As for other things like you may need advice whether this job is good for you etc --- pray Istikhara
and you can also say other dua's in times or worry or anguish etc
I have included a link to a very good site on dua's inshaAllah you find it beneficial.