This is actually possible from your project as well, no need to start the emulator through the AVD manager:
-
Go to
Run > Run Configurations… > (Select your application on the left hand side) > (Click the"Target"tab on the right hand side). -
At the bottom there, you’ll see
Emulator launch parameters. In theadditional emulator command line options, add'-scale 0.75'(to make the screen 75% of full size)
Next time you start the emulator it will have scaled properly.