Jobs at small Fresno companies nobody posts about - any advice?

Two small Fresno employers told me they are hiring but have not posted yet. They prefer people who can start within a couple of weeks. What do you write in a cold email?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

A short email with two sentences about what you can do and your résumé attached worked for me. I followed up after a week.