To use the following commands you need to have the Tesla application installed on your phone and open in the background. If you don't, Siri will ask you to open it. We've also found that the phone needs to be unlocked.
We've also found that if the car is asleep, Siri won't wait long enough for the car to respond. But, its a bit of fun and we thought you'd like to know.
If you have set only the drivers door to unlock, just say "Hey siri unlock my car door" a second time after the driver's door has unlocked.
A couple of troubleshooting tips, you need to have Siri & Search turned on in the settings (Settings -> Tesla). We've also found that older versions of the app and/or iphones don't have the use with Siri option.
Siri controlling summon is probably a step to far, but it would be cool if you could say "back a bit, a nit more.. keep coming..". One day maybe!!