Wash and cut potatoes in half.
Place 1 cup of water and the potatoes into the steamer basket in the Instant Pot.
Close lid and vent on Instant Pot and press manual 8 minutes.
When 8 minute cycle is done, press cancel and let naturally release for 5 minutes.
Release pressure, open lid, and remove potatoes with tongs.
Add washed and prepped green beans to Instant Pot, close lid, close vent, and cook on manual for 1 minute
When beans are done, quick release, remove steamer basket carefully, and place in an ice water bath for 1 minute, then drain.
While potatoes and beans are cooking, pour wine into a small pan, cook on medium low, and simmer for 6-8 minutes until reduced by half.
Whisk oil, vinegar, and reduced wine together. Mix in mustard, salt, and pepper.
Peel potatoes once slightly cooled (you can leave the peels on if you like them on).
Combine potatoes, beans, herbs, and oil/wine mixture together in a large bowl and stir gently until thoroughly mixed.
Refrigerate for at least one hour or overnight.