Extract icons from apps with a service. Add Filter Finder Items action (Kind:Apps) and Run Shell Script action with the following script.

Extract Icons Service.sh

mkdir $HOME/Desktop/AppIcons/

for CURRENTAPP in "$@"; do
	APPDIR="$1"
	ICON=`defaults read "$APPDIR/Contents/Info" CFBundleIconFile|sed -e 's/\.icns$//'`
	ICONFILE="$APPDIR/Contents/Resources/$ICON.icns"
	APPNAME=`basename "$APPDIR" .app`
	OUTFILE="$HOME/Desktop/AppIcons/${APPNAME}.icns"
	cp -f "$ICONFILE" "$OUTFILE"
	shift
done