Place the whole potatoes, salt, and water in a medium saucepan. Add more water if necessary to cover the potatoes by about an inch. Bring up to a boil. Placing a lid on the pot will cause the water to boil quicker.
Cook the potatoes just until fork-tender, approximately 25 to 30 minutes total.
While the potatoes are cooking, to a medium bowl add the mayo, yogurt, Salt ‘n Vinegar seasoning, celery seed, and mustard. Whisk well and taste. It should taste quite salty. The saltiness will be dispersed throughout the finished potato salad.
Once the potatoes are finished cooking, drain them. Allow the potatoes to 1 cool to be able to handle them.
Cut the potatoes into quarters and add them to a large bowl. Add the bell pepper, red onion, 2 tablespoons of the green onions, eggs, celery, and 2 tablespoons of the parsley. Gently toss all the vegetables together.
Add the Salt ‘n Vinegar mixture to the potatoes and veggies, gently tossing everything together.
Taste. Add more of the Salt ‘n Vinegar seasoning and black pepper, if desired. Top with the remaining green onions and parsley.
Serve, or cover and refrigerate for up to 5 days. (See post above for tips about seasoning and serving the potato salad on a later date.)