Thanks.
I don't understand why this user informations are not actually exposed on the /user api.
So, I create a new UserProperty called UserViewsProperty (source code in attachment) and integrate it in a plugin.
This solution required me to create an empty config.jelly for the /user/configure page. My skills on Jenkins core being insufficient, I haven't really understood why.
When I call the user api, I 've got now a new property called "userViews"
In any case, it works but I'm interested in any comments or another type of solution.