I followed this guide to make escape quit from various modes...
;; esc quits
(defun minibuffer-keyboard-quit ()
"Abort recursive edit.
In Delete Selection mode, if the mark is active, just deactivate it;
then it takes a second \\[keyboard-quit] to abort the minibuffer."
(interactive)
(if (and delete-selection-mode transient-mark-mode mark-active)
(setq deactivate-mark t)
(when (get-buffer "*Completions*") (delete-windows-on "*Completions*"))
(abort-recursive-edit)))
(define-key evil-normal-state-map [escape] 'keyboard-quit)
(define-key evil-visual-state-map [escape] 'keyboard-quit)
(define-key minibuffer-local-map [escape] 'minibuffer-keyboard-quit)
(define-key minibuffer-local-ns-map [escape] 'minibuffer-keyboard-quit)
(define-key minibuffer-local-completion-map [escape] 'minibuffer-keyboard-quit)
(define-key minibuffer-local-must-match-map [escape] 'minibuffer-keyboard-quit)
(define-key minibuffer-local-isearch-map [escape] 'minibuffer-keyboard-quit)
(global-set-key [escape] 'evil-exit-emacs-state)
To make helm quit using escape, I tried:
(define-key helm-map [escape] 'helm-keyboard-quit)
This didn't work. Setting other keys instead of escape works fine though.