Genji Shimada shouts “Ryujin no ken wo kurae!” when he uses his ultimate, which roughly translates to “Take my Dragonblade!”. Hanzo Shimada shouts “Ryuu ga waga teki wo kurau!” when he uses his ultimate, which roughly translates to “Let the dragon consume my enemies!”.
Translated: eat the blade of the dragon god
竜神の剣を喰らえ ryujin no ken wo kurae.
Genji – “Ryu jen no ken wo kurae” which means “The dragons becomes me”
Genji’s is a bit trickier:
ryujin – portmanteau “dragon – man”
no – ‘s
ken – sword
wo – marks the object
kurae – eat (vulgar, command)
So “eat the sword of the dragon-man”. If he’s using the demon skin, he changes ryujin to oni which becomes “eat the sword of the demon”.
The issue with Genji’s is that it’s much more different from the given English translation (“the dragon becomes me”) than Hanzo’s is, and also a bit out of character for the English Genji. I actually like the suggestion below that he’s actually saying kure “lend”, but if you listen to the Japanese localization of Overwatch, both Genji and Hanzo have the same ultimate lines but with much stronger Japanese accenting and it’s clearly kurae.