@Anonymous, nor am I!! 
Within Flow there isn't a way to do this, but why would you want to open the email before it goes? Normally everything you want in the email can be built into the flow. What would you do in the email if you were able to open it? As always, a screenshot of the flow would help.
Rob
Los Gallardos
If I've answered your question or solved your problem, please mark this question as answered. This helps others who have the same question find a solution quickly via the forum search. If you liked my response, please consider giving it a thumbs up. Thanks.