In my poor opinion, there is no such term in the "special cricket terminology". There are in the list of cricket terms only the following close to the mentioned of you above term, namely on side, on strike, on the up (there is only a faint likeness- presence of on).
Presumably this is an ordinary idiom.
on fire = 1. ignited; ablaze
2. filled with enthusiasm or excitement
Happy New Year.
Student or Learner