New here, Blynk rocks! This may already exist in the Blynk docs. I didn’t read much going as quickly as possible to setup a Particle device and see its data.
Suggestion: for each device shown in the Dashboard, make the Auth Token a hot link that copies it to the clipboard.
For those starting with Blynk, and looking for the auth code for the device, for example when setting up a Particle device integration 
- click on Devices on the left in the Blynk Dashboard
- click on the device
- click on Developer tools, the tiny green tools shown here
