Emitting a key with no definition (unicode characters)

[felagund]

This is possible with xmodmap: https://askubuntu.com/questions/429946/custom-keyboard-layouts-adding-a-character-for-which-no-keysym-is-defined

Is it possible with KBCT? I would like to type some typographical symbols like proper quotation marks or a dash etc. No idea how I should name the keys.