(Android) Launch app activity shortcuts from the command line?
Looking for an intent interceptor I came across IntentTask which is helpful for your objective. I installed Tasker, that app, setup a Task with action: 

Plugin &rarr; IntentTask &rarr; Launch Shortuct &rarr; Configuration: tap pencil icon &rarr; your app &rarr; the profile. 

The intent auto-populated there was: 

#Intent;action=org.strongswan.android.action.START_PROFILE;l.org.strongswan.android.VPN_PROFILE_ID=1;end


You can now attach your task to a boot profile in Tasker now. 

As for the command-line I tried the same intent in the command-line and it works too.

am start -a org.strongswan.android.action.START_PROFILE --el org.strongswan.android.VPN_PROFILE_ID 1


Replace 1 with the your profile's ID.