This achievement is for Parasoul:
I don't believe these achievements can be earned in training mode, so go into local versus with a second controller. After the round starts, hold start and turn on Sparring Mode. This will basically make it act like training (infinite time/health).
I just spammed her little helpers for a while (charge back -> forward + Kick) and it eventually unlocked. Godkarp tells me 100 times, sounds about right to me. I switched up between light,medium,heavy.
Just keep at it and eventually it'll unlock.