Advise on preparing walls in kitchen for re tiling

[Rb1980]

Hi all am changing tiles in my kitchen ans expect to damage the walls removing tiles . Think the walls are Plaster board with skim coat . What’s rhe best thing to use to fill any holes or smooth over ? Will be tiling the area next to the gas hob so it’ll get quite warm and I see thistle one coat only has a temp recommendation of max 50 degrees ? Thanks