You don't need to use the GUI to initiate a PuTTY connection. I actually prefer to just launch it from the Windows Run dialog or a powershell/cmd prompt most of the time.
The Help button in the screenshot you posted will open the PuTTY User Manual. In it, there's a whole section called The PuTTY command line within the section called Using PuTTY. Specifically, section 3.8.3.5 is all about port forwarding. From the manual:
As well as setting up port forwardings in the PuTTY configuration (see section 4.25), you can also set up forwardings on the command line. The command-line options work just like the ones in Unix ssh programs.
To forward a local port (say 5110) to a remote destination (say popserver.example.com port 110), you can write something like one of these:
putty -L 5110:popserver.example.com:110 -load mysession
plink mysession -L 5110:popserver.example.com:110
To forward a remote port to a local destination, just use the -R option instead of -L:
putty -R 5023:mytelnetserver.myhouse.org:23 -load mysession
plink mysession -R 5023:mytelnetserver.myhouse.org:23
Based on your example, the command line would be something like this.
putty -L 7456:someurl.com:7456 -ssh A.B.C.D:8080
Also if you actually want to know how to use the GUI for setting up a tunnel, that's in section 4.25 called The Tunnels panel.
