How did Kuroko's vanishing drive affect Momoi? According to this wiki page:


  If the vanishing drive based on pushing the opponents to focus attention to someone else and then steps in unexpectedly. 


And also:


  Kuroko uses his misdirection in function of his teammates. He must make eye-contact with the passer while doing his misdirection and so the eyefield of the other players becomes a "mirror" for Kuroko's position.  


How is it that Momoi was affected by it when Kuroko showed to her for the first time, when no other player was around?
The way the vanishing drive works is that he diverts their attention for a split second, and is then past them by the time they realise what he's done. Against skilled players in a proper game, he needs something with a huge presence, such as Kagami or Aomine to make them forget about him, and that's the real trick, distracting someone when they're completely focused on you. 

However Momoi is not a competitive basketball player and they were not playing in an actual game, so my best guess is that he was able to use something with far less presence than he would normally need, like a street lamp or a car or whatever was nearby.