Can I install apps on "/home" / home directory instead of "/usr" directory?

I am trying to dual boot on my laptop. And i have decided to create two partition in my ssd and hdd. I want create a partition in ssd for "/" root directory and a partition in the hdd for my "/home" directory of my ubuntu setup. And now my question is, Where will be "/usr" user directory will be set? Is it on the ssd partition? And by default, where are apps that i installed is set? I have come to know that its the user directory. Can i change the directory of apps installing to "/home" directory instead of "/usr" directory? Because, I dont have many space on my ssd. Thanks in advance...