How can I use a file that is inside resource .res?

[Marcone]

I created a file called "resource.rc" with this content:

1 ICON icon.ico
2 EXE app.exe

And compiled with this command:

windres.exe resource.rc resource.res

And I binf it to my program with this command:

dmd Program.d resource.res

Now I have a Program.exe with "app.exe" inside.

Now the file "app.exe" is inside my program, but how can I use 
this file? How can I extract this file?