Congrats for your new Ninja! If it pings, it goes away on its own after use. If it really bothers you (are you a teenager with very sensitive hearing?), you can open up the case and de-solder the switch, open up the switch lubricate the switch and you are good to go.
Really, you don't need to do any of those. They are last resorts. It will go away. Trust me, I have 6 Filcos cherry boards. ;-) whatever you do, just don't squirt it with expanding foam from hardware stores.