Start by placing petite white or red potatoes in a large pot filled with cold water and a generous pinch of kosher salt. Bring to a boil over medium-high heat, then simmer for about 15 minutes until fork-tender yet firm. Drain and cool slightly.

In a clean jar or bowl, combine extra-virgin olive oil, red wine vinegar, minced garlic, dry mustard, dried thyme, oregano, kosher salt, and ground black pepper. Shake or whisk until emulsified and smooth.

Once drained, allow the cooked potatoes to cool slightly. Ensure they soak up flavors without falling apart.

While warm, drizzle reserved caper brine over potatoes. Gently fold in olives, sliced red onion, sun-dried tomatoes, capers, and fresh dill.

Pour the prepared dressing over the potato mixture and gently toss to coat, adjusting seasoning with additional salt or pepper if desired.

Just before serving, sprinkle crumbled feta cheese on top and let the salad rest for at least an hour in the refrigerator.