Begin with 2 lbs of petite white or red potatoes, placing them in a large pot. Cover with cold water, adding kosher salt. Bring to boil and cook for about 15 minutes until fork-tender. Drain and cool slightly.

For the dressing, combine olive oil, red wine vinegar, minced garlic, dry mustard, thyme, and oregano in a jar. Season with salt and pepper. Shake until emulsified.

Cut cooled potatoes into halves or bite-sized pieces. Drizzle caper brine over them.

In a bowl, combine potatoes, Kalamata olives, sun-dried tomatoes, capers, and red onion. Add dill and dressing, toss gently to combine.

Adjust seasoning if needed, sprinkle feta on top, and refrigerate for at least 1 hour before serving.