When adding, moving and resizing blocks in the editor, sound effects will play.
To turn them off, first tap the three dot [...] button in the lily pad to view Grid Controls.
Within Grid Controls, tap "Sounds on" to toggle the sound off. The button will then display "Sounds off" to confirm this action.
Once turned off, sounds will remain off for all future editor usage. If you wish to turn them back on you can always tap that buttong again!