You can, but it isn't quite as straightforward as you assume. A package isn't guaranteed to provide exacty one executable. Indeed, many provide multiple executable programs. For an obvious example, consider coreutils which provides basic GNU utilities like cat, chmod, ln, split and so on. So there is no "its binary" when talking about packages. Instead, you can get a list of the various binaries a package may provide.
Pedantic note delivered, let's see how to actually do it. I would just look for files included in the package that are installed in the various bin directories. Something like:
$ pacman -Ql gnome-console | awk '($2~/bin\/./){print $2}'
/usr/bin/kgx
The command pacman -Ql PACKAGE_NAME prints out the list of files and directories the package will touch, with the package in the first field, and the file/dir as the second:
$ pacman -Ql gnome-console | head
gnome-console /usr/
gnome-console /usr/bin/
gnome-console /usr/bin/kgx
gnome-console /usr/share/
gnome-console /usr/share/applications/
gnome-console /usr/share/applications/org.gnome.Console.desktop
gnome-console /usr/share/dbus-1/
gnome-console /usr/share/dbus-1/services/
gnome-console /usr/share/dbus-1/services/org.gnome.Console.service
gnome-console /usr/share/glib-2.0/
So we pass that through an awk command that prints the 2nd field if the 2nd field matches bin/ followed by at least one more character. This is to avoid printing out /usr/bin itself. Note that this assumes no spaces in any of the paths, which really should be a safe assumption here, but for the sake of completeness, here's one that can also deal with spaces (not in the package name as that isn't allowed):
$ pacman -Ql gnome-console | perl -ne 'print if s|^\S+\s(.*bin/.+)|$1|'
/usr/bin/kgx
And, just to illustrate the point in the first paragraph:
$ pacman -Ql coreutils | perl -ne 'print if s|^\S+\s(.*bin/.+)|$1|'
/usr/bin/[
/usr/bin/b2sum
/usr/bin/base32
/usr/bin/base64
/usr/bin/basename
/usr/bin/basenc
/usr/bin/cat
/usr/bin/chcon
/usr/bin/chgrp
/usr/bin/chmod
/usr/bin/chown
/usr/bin/chroot
/usr/bin/cksum
/usr/bin/comm
/usr/bin/cp
/usr/bin/csplit
/usr/bin/cut
/usr/bin/date
/usr/bin/dd
/usr/bin/df
/usr/bin/dir
/usr/bin/dircolors
/usr/bin/dirname
/usr/bin/du
/usr/bin/echo
/usr/bin/env
/usr/bin/expand
/usr/bin/expr
/usr/bin/factor
/usr/bin/false
/usr/bin/fmt
/usr/bin/fold
/usr/bin/head
/usr/bin/hostid
/usr/bin/id
/usr/bin/install
/usr/bin/join
/usr/bin/link
/usr/bin/ln
/usr/bin/logname
/usr/bin/ls
/usr/bin/md5sum
/usr/bin/mkdir
/usr/bin/mkfifo
/usr/bin/mknod
/usr/bin/mktemp
/usr/bin/mv
/usr/bin/nice
/usr/bin/nl
/usr/bin/nohup
/usr/bin/nproc
/usr/bin/numfmt
/usr/bin/od
/usr/bin/paste
/usr/bin/pathchk
/usr/bin/pinky
/usr/bin/pr
/usr/bin/printenv
/usr/bin/printf
/usr/bin/ptx
/usr/bin/pwd
/usr/bin/readlink
/usr/bin/realpath
/usr/bin/rm
/usr/bin/rmdir
/usr/bin/runcon
/usr/bin/seq
/usr/bin/sha1sum
/usr/bin/sha224sum
/usr/bin/sha256sum
/usr/bin/sha384sum
/usr/bin/sha512sum
/usr/bin/shred
/usr/bin/shuf
/usr/bin/sleep
/usr/bin/sort
/usr/bin/split
/usr/bin/stat
/usr/bin/stdbuf
/usr/bin/stty
/usr/bin/sum
/usr/bin/sync
/usr/bin/tac
/usr/bin/tail
/usr/bin/tee
/usr/bin/test
/usr/bin/timeout
/usr/bin/touch
/usr/bin/tr
/usr/bin/true
/usr/bin/truncate
/usr/bin/tsort
/usr/bin/tty
/usr/bin/uname
/usr/bin/unexpand
/usr/bin/uniq
/usr/bin/unlink
/usr/bin/users
/usr/bin/vdir
/usr/bin/wc
/usr/bin/who
/usr/bin/whoami
/usr/bin/yes
Alternatively, since it might be the case that some executable files are not installed in bin directories, you could iterate over the list of files and look for regular files that your user can execute:
$ pacman -Ql PACKAGE_NAME | cut -d ' ' -f2 |
xargs -I {} bash -c '[[ -x "{}" && -f "{}" ]] && echo "{}"';
In the case of coreutils, that includes one more file:
$ pacman -Ql coreutils | cut -d ' ' -f2 |
xargs -I {} bash -c '[[ -x "{}" && -f "{}" ]] && echo "{}"' |
grep -v bin
/usr/lib/coreutils/libstdbuf.so
