Or, the alternative, they dress in black, infiltrate your building, and then gouge your eyes out and deliver them to their client. If you think of them that way, then yes, they can be a good ninja.
Okay, I can accept that perspective. But that's not exactly in the way they mean it in Silicon Valley. In Silicon Valley, when they say "deliver eyeballs like a fucking ninja," they mean, "I'm can get a quarter-million people to look at your website." Obviously, that means quite something different than carving peoples' eyes out, after which they won't be able to see any websites.