Place the halved baby potatoes in a large pot and cover with cold water. Add the salt and bring to a boil. Cook for 12 to 15 minutes until the potatoes are tender but still hold their shape.
Drain the potatoes and spread them on a baking sheet to cool for 10 minutes. This step keeps them from getting soggy when dressed.
In a large mixing bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, salt, and black pepper.
Add the cooled potatoes to the bowl along with the sliced red onion. Toss gently to coat everything evenly with the dressing.
Sprinkle the chopped dill, parsley, and crumbled feta over the top. Toss once more just before serving so the herbs stay fresh and the feta does not break down.