Yup, you'll definately need 2 brushless esc's as they sense the position of the motor as it spins round, enabling it to operate properly, and they won't syncronise to operate together if thats what you might think.

If you was to use a brushed motor set up, then thats the only way you can get away with a single esc.

You'll be able to get away with a single lipo pack though depending upon the C rating it has.
You won't blow it as such as long as you do your homework first and choose one that can handle the current that both motors will be taking at once.
By choosing one with a high capacity and high C rating, you'll easily do it.

Something of the 3000 to 4000 mah of 20C rating would be ideal.