menu.clj

(def data
  [["Community" "community.png" "Community"]
   ["News"      "news.png"      "Community"]
   ["Messages"  "messages.png"  "Community"]
   ["Inbox"     "inbox.png"     "Messages"]
   ["Sent"      "sent.png"      "Messages"]])

(defn map-menu [menu]
  (reduce (fn [m [child image parent]]
            (let [children (-> (:children (get m parent) #{})
                               (disj parent)
                               (conj child))]
              (-> (assoc-in m [parent :children] children)
                  (assoc-in [child :image] image))))
          {}
          menu))

(defn map->tree [m root]
  (let [{:keys [image children]} (get m root)]
    {root {:image image
           :children (map (partial map->tree m) children)}}))

(map->tree (map-menu data) "Community")

;; {"Community" {:image "community.png", 
;;               :children ({"Messages" {:image "messages.png", 
;;                                       :children ({"Inbox" {:image "inbox.png", 
;;                                                            :children ()}}
;;                                                  {"Sent" {:image "sent.png", 
;;                                                           :children ()}})}}
;;                          {"News" {:image "news.png",
;;                                   :children ()}})}}

Awesome