Hey Massaki,
since Kanso in responsive, i.e. adapts to the smaller screens via CSS rules, there’s not way to request a desktop website as long as the screen width is still small. To disable the mobile layouts completely, you’d need to remove everything from line 430 and down in the theme’s “responsive.css” file – I’ve prepared one for you, please download this archive, unzip it, and upload the resulting file into the theme folder. Better still, I would advise to implement this via a child theme (more information here) – this way the changes will stay even if you decide to update the theme in the future.
Sincerely,
Andrii / Satori Stuido