In a small mixing bowl or glass measuring cup, whisk together the extra-virgin olive oil, red wine vinegar, pepperoncini brine, garlic powder, fine sea salt, and black pepper until emulsified.

In a large salad bowl, combine the diced English cucumbers, diced green bell pepper, minced red onion, chopped pepperoncini, and chopped parsley.

Gently fold the chopped hard-boiled eggs and roasted sunflower seeds into the vegetable mixture.

Drizzle the prepared vinaigrette over the salad and toss gently until all components are evenly dressed.

Let the salad rest for 5 to 10 minutes at room temperature before serving, or chill in the refrigerator to allow the flavors to marry.