You can enable an approval (content/target) in the recurring delivery (so that the delivery does not go out without the approval and validating the proof). Then open the delivery from the campaign dashboard and now you will be able to see the 'Send A proof' button.
For test purposes and for the sake of sending a proof using a live profile with dynamic data coming from the workflow, why don't you use a standard delivery in the workflow and set the action to perform to 'Send a proof' and use the substitution of address method? This would be for testing only, once you are happy with the proof you can then use the recurring delivery for the actual live send of the campaign.
Alternatively you could have a test recipient with your email address for which you can populate the dynamic fields and add the test recipient to your workflow. Before the delivery activity I would have a split in place to filter on your recipient only, to ensure only your test recipient is being targeted and send the email this way. However this would be a real send to your test recipient and not a proof therefore it can impact reporting at a later stage. I would also recommend keeping the delivery activity on 'Enable but do not execute' so you can display the target and ensure it is only your test recipient that will get the email. Once you verify this you can set it to 'Normal execution' and resume the workflow by clicking the play button (not restart the workflow). Personally I'd go with the first option.
Aside from that, I am not aware of a way to send proofs using a recurring delivery.