If your charger will charge two calls at one amp each, the wall wart is at least two amps.
I have several wall warts left over from phones and bluetooth devices. 1/2A, 1 A, 1.5A and 2 A.
I use the 1/2A to charge 18350s at 1/4A. The others for 18650s, depending on how much time I have.