Short version: they looked a lot more like 
than 
. Most accounts of Vikings that are contemporary of the centuries where shield-Danes and spear-Danes went "a-Viking" describe distinctly hygenic people that bathed and took care of their hair (and wore it long).
EDIT: I thought I could have a little fun with a very loosely associated Beowulf reference to Danes (and even more loose associations with Geats therein too) but I got the 
experience for doing so. 
They didn't have Hitler Youth fades with lazy and sloppy beard fusions. Period. Full stop. Stop doing that. Looking right the fuck at you too, P R E S T I G E T V. 
On the vikings encountering Jewish people, its very possible the Varangians encountered the Khazars on their way to Constantinople; and according to some sources their Nobles converted to Judaism around the same time as the Viking age. Ahmed ibn Fadlan funnily enough, on his trip where he documented his encounter with the Rus vikings, wrote about them and said "the core element of the state, the Khazars, were Judaized"
The ancient world was way more interconnected than a lot of people think.
not Viking times as much but another possible jewish steppe clan are the Seljuks before their conversion to islam, olde poppa Seljuq's kids had first testament names---also cudda been Nestorian tho
judaism was common enough in inner asia, they got to China in the T'ang or Sui dynasty