I applied through university. The process took 1 day. I interviewed at ICSI (Berkeley, CA)
Interview
Rather informal and painless for junior staff. For more senior folks, you're expected to spend a day at ICSI giving a talk on your research work and cycling through interviews with staff.
I saw a post online and applied to the job by sending an email to the researchers that were hiring. I had an interview where they asked me about my technical background, projects that I had worked on, and my familiarity with math and signal processing.
Interview questions [1]
Question 1
I wasn't really asked any tricky technical questions. They just asked about projects I had worked on and what skill I learned through them.