I'm not 100% sure, but I think that touch input would need to be integrated into the asset you're using.
I don't think you can have touch input simulate a key press, so you would need to code the touch input to actually do the action you need, which is tied to the asset you're using.
I'm really not experienced on the topic though, so you might want to include more details, like which asset you're using, so that someone else might be able to help.