halacha - After cutting my hair, how many times must I wash my hands?

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.)

Answer

See the Shaarei Teshuva, a commentary which is printed in most editions of the Shulchan Aruch.

The Shaarei Teshuva on Orach Chaim 4:12, citing the Machzik Bracha, writes that getting out of bed in the morning needs three times and a vessel, but other things (bathroom is a machlokes) do not. Why? Because the ruach ra'ah is not the same level as when one sleeps. However, he mentions two things which do require three because of tumah. Since cutting hair is not mentioned (in the Shaarei Teshuva) it would seem that any washing would be sufficient.

If a vessel is available and there is enough water then one should be concerned for the stringent opinions (cited below) which hold that one does need three pours and a vessel. (Piskei Teshuvos 4:18:169). However, the Shaarei Teshuva seems to hold that to be unnecessary.

Regarding shaving, the Piskei Teshuvos (4:28, footnotes 262, 263, and 264) writes that only cutting the hair of the head requires washing not shaving (Rav Shlomo Zalman Auerbach). Cutting other people's hair also require washing but when being honored by an upsherin one does not need to wash for cutting of a few hairs.

For an in depth analysis of this topic the Piskei Teshuva 4:18 goes through the four classes that require washing. In that se'if, he explains and goes through many of the shittos, including the halachic side and kabbalistic side. He also brings the Shaarei Teshuva mentioned above.