Rex's suggestions in #1 were both new to me, so just for my own information ...
How does Klatsche compare to something like
fertig machen, vernichtend schlagen, in die Pfanne hauen ?
Those are some of what I found when I looked up rough synonyms for 'whomp,' like whip, whop, whup, shellac, cream, clobber, paste, thrash, crush, slaughter ...
Does 'Klatsche' in that sense mean something like a blow with a flyswatter? My dictionaries list the sense of a smack or slap under Klatsch rather than Klatsche; is that a regional thing?
For 'edge,' could you say 'knapp,' or is that already implied by 'ausstechen'?