The simplest way is with kisslicer itself, by adjusting the offset on the style tab. Adjusting it to a negative value is resulting in an expanding in XY plane. In my experience the value has something between 0 and - 0.2mm depending of the model. Slice and inspect the results so that on all spots there is at least one extrusion resulting. Important as well for a good result is to set the oversample resolution not to heigh (I use 0.07mm on delicate prints) and the crowning to 1mm. These last settings on the 'misc' tab (pro only)
But I'm curious as well if there are other ways in a modeller or repair program. Earlier attempts of me to do that in Magics (negative shrinkwrap) or meshmaker had not a good result.
Bart