guaca is a redirector for Guacamole that enables you to use adhoc sessions, i.e. without having to configure the connection a priori.
You can simply call
http://localhost:8080/guaca?hostname=SOMEHOSTNAME&protocol=ssh to get an ssh session to SOMEHOSTNAME (assuming that your Tomcat server runs on port 8080 on localhost).
Please note that you'll need the NoAuth extension for Guacamole. See also https://ogris.de/guaca/