Shulchan Aruch, Orach Chaim 4:19 says:
One who takes a haircut or shaves and does not wash his hands, will be scared for three days [...] and [...] will not know what he is scared of.
(Translation credit: Wikisource. To see the Hebrew original, see this page of the Mishnah Berurah. R' Ze'ev Greenwald adds that "the hands must be washed immediately". The Institute for Dayanim notes that ritual handwashing might not actually be necessary after shaving.)
I tend to cut my own hair. (Since I own an electric hair clipper, it's not that difficult.)
The Shulchan Aruch says I must wash my hands, but it doesn't say how many times I must wash each hand.
Can I just rinse my hands (both at once) under a stream of running water from the tap, or must I pour water from a vessel? If I must use a vessel, then how many times must I pour water on each hand?
(Please cite a source. In case it matters, I'm Ashkenazic.)