How can I launch Chrome with flags from command line more concisely?

Just make an alias in your .bashrc or .bash_profile

alias ogc="open -a Google\ Chrome --args --disable-web-security"

And then reload your shell.

exec $SHELL

Now, every time you type ogc (or whatever you want to call it) in your terminal, it will run the full command open -a Google\ Chrome --args --disable-web-security