Since there are no separate grips and the grip frame is polymer, your options are limited.
One would be to use fine wet or dry sand cloth to reduce the abrasive texture.
Another would be to sand it off completely then stipple the frame.
This is usually done with n electric soldering pencil and a shaped tip.
Some custom gun smiths can build up a polymer frame by plastic welding to reshape it.
This is most popular on Glock's but a Kahr can be done.
The easiest method is to buy a rubber slip-on grip sleeve.
These are sold by Hogue and Packmayr.
This will change the feel of the texture and increase the size.
