Scrub potatoes thoroughly under cold water.
In medium saucepan, boil on stovetop in lightly salted water until tender, 18-25 minutes, depending on the size of the potatoes.
Cool until manageable, then cut into 3/4" dice.
In large bowl, toss diced potatoes together with olive oil and garlic.
Cool potatoes to room temperature.
Add feta and scallions to the potatoes and drizzle with vinegar.
Add dill and season to taste with salt and pepper.
Allow salad to sit for at least an hour for flavors to meld before serving.
Serve cold or at room temperature.
Refrigerate leftovers.