Add salt to taste or cookup your own recipe based on the hints here.
(add-hook 'org-mode-hook
(lambda nil
(setq-local default-text-properties
'(point-entered org-link-entered-maybe))))
(defun org-link-entered-maybe (op np)
(when (derived-mode-p 'org-mode)
;; (message "In org-link-entered-maybe")
(let* ((inhibit-point-motion-hooks t)
(ctx (org-element-context)))
(when (eq 'link (org-element-type ctx))
(tooltip-show (org-element-property :raw-link ctx)
(not 'use-echo-area))))))
