这是一个省略了成分的修辞性问句。问句省略了is there。补上省略的成分则问句如下：

And what better way is there to answer skeptics from any group than by certifying the technical skills of graduates from a national service program?

修辞性问句是不需要回答的。有比...更好的方法吗？没有！所以这个问句等于强烈的否定句：

And There is no better way to answer skeptics from any group than by certifying the technical skills of graduates  from a national service program.

这个句子其实表达的是最高级的意义：

Certifying the technical skills of graduates  from a national service program is the best way to  answer skeptics from any group.