Did I describe the following concept correctly? In a discussion, my meditation leader was talking about people who cannot control their cravings and wants, who are easily subjected to actions based on their whims and wants of their anger. He associated these people with having akusala thoughts. He could not find the English word to describe the person, and so I gave him the word impulsive as a way to describe these people. 

Was this the right word to use, and is there a better word that I could have used?
That's a great translation.  Other words that may fit like impulsive


hasty
imprudent


@ChrisW mentions in a comment that kusala means skillful, so a +kusala would mean the negation of kusala (if you look at how sanskrit works), thus another word may be unskillful  and it sounds like your meditation friend was trying to expound on what that term actually means.

Many words have nuances that can become lost in translation, so sometimes it is good to leave words untranslated, or look at how they were constructed.  For example: we could not say "pulsive" as the negation of "impulsive" even though "possible" and "impossible" have the same relationship as "kusala" and "akusala" -- it just depends.  Again, good translation, but be open to the idea that not everything need be translated (and thus nuance can be ushered into a new language body and preserved)