Some ESC's come with a "arming" switch that only controls power from the BEC to the electronics.

If your ESC doesn't come with one, you could always disable the on-board BEC, then hook up a separate BEC via a switch.

That way your ESC is powered up when you hook up the battery, but the TX remains off and inactive until you flip the switch.

IMHO this is more grief than it is worth ( I'd go with an arming switch first )...

Your ESC probably already has it's own software "arming" proceedure. That is what I typically rely on.

Remember the Arming switch and BEC switch both introduce "points of failure".... heh...