I’d like to list all binary executables in a particular folder hierarchy. How can I do that?

All Mac OS X binaries are so-called Mach-O executables. You can utilize this in the following way (all on one line):

for item in `find . -perm -0100 -type f` ; do file $item | grep 'Mach-O' ; done | awk '{print $1}' | sed 's/\:$//'

This shell command will generate a list of every file which is a Mach-O executable for at least one architecture, starting recursively in the current directory.