Try going to the Wear app on the phone, tapping the tips & and user guide then tapping the giant "what's new" panel on top. There's a section titled "take your running to the next level". If you tap that, you can use the "try it" button to take the 12 minute test. This may or may not bring the option back to the watch. I was under the impression that the coach appears once, and if you dismiss it, it does not come back. It may stay if you take the test and set up a plan, I don't know as I dismissed it the minute I saw it and never saw it again.
