You can choose the font that Kiten uses in its result view. Go to the Kiten configuration dialog, which can be opened by choosing → . Select the Font page of the dialog and select the font in the font-chooser.
Qt™ 's font-substitution system makes it so a Japanese font will always be substituted for Japanese characters, even if the font you specify doesn't include them. Thus, you can choose any font in the chooser and everything should still display fine.