Ask HN: What's the right way to do email-based customer development?

I think many of us have been in this situation: You get your startup's name listed somewhere and suddenly sales emails targeted at your startup start flooding in.

I don't want to do this or otherwise annoy people. I have a startup idea that I want to validate based on some recent experiences and it looks like my best shot at getting good feedback is via email.

Is there an acceptable way to ask early-stage founders for an interview via email without coming off as a spammer with something to sell?