To get access to the helpers I did three things...
I updated the first line of file jquerypp/view/helpers/helpers.js from:
steal('jquerypp/view/ejs').then(function($){
to
steal('jquerypp/view/ejs').then(function(){
I stole 'jquerypp/view/helpers' in the controller.
Finally, in the ejs instead of
<%= select_tag('elementId', 1, this.choice) %>
I used
<%== select_tag('elementId', 1, this.choice) %>
to force ejs to render the select block as part of the page instead of rendering an escaped quoted version.