I have found that almost any decently sized company uses some sort of online form as part of the application/interview process. These forms usually have a current or desired salary field and often has fairly strong validations on it (e.g., must be filled in, must be a number between x and y, no non-numeric characters allowed). So you either have to fill it in or not submit the application form at all (the rest of whi…
For a specific company, you should have an inside connection. Get referred by an employee, get contacted by a recruiter who works specifically with them, or even cold-email an HR/manager. Anything's better than putting your resume in the big pile full of spam.
However you do it, when you get to the point where you're talking with the hiring manager and they like you enough to interview more, they may say "HR needs you to fill out our application here before we can bring you on-site," and then it's OK to do so. You shoot the manager a quick note "I'm not ready to talk salary yet, but the form had some validation on it so I just put in '99,999' don't worry about it; it's just a placeholder". Or you hack the form to submit something funny and that's even better.