K.W.
At 14 mos, it is difficult to teach her how to be appropriate. It would probably be best to distract her from the children at the playground by engaginer her in play. Then, when a child is close to her and she want so hug, perhaps teach her to invite a hug by stretching out her arms. Other 14month-olds may recognize that as an invitation to hug and respond. If they choose not to hug, mommy can give her a hug and lots of lovin'.
As far as hitting other children,I think another response mentioned, that your child does what you do. So, if it is ok for mommy to pop her hand, it is ok for her to pop other children, mommy, daddy whoever. Children do what they are taught. When she is popped in the hand, she learns that it is ok to pop someone in the hand when they do something you don't like. She doesn't understand that she could get seriously hurt touching something. But she is learning that mom will hurt her and that it is ok to hurt others.
Another thought, since the outlets are covered, dhe could safely touch it. Her fascination with it could be the attention she gets when she goes near it. If the outlet got no reaction, no danger warning, no hitting no alarms went off. Why in the world would she want to touch it. It doesn't do anything, it's not shiny. The outlet itself holds no attraction. The attraction is the reaction it gets.
Just my thoughts.
K.
mom to two