Bring a large pot of salted water to a rolling boil. Add frozen peas and cook for 5 minutes until vibrant and tender. Drain and set aside to cool.

In a small saucepan, heat olive oil over medium flame and sauté minced onion for 5 minutes until translucent. Remove from heat and whisk in white wine vinegar.

In a mixing bowl, pour the onion dressing over the warm peas. Gently fold in sliced radishes, chopped mint, and chives.

Transfer the mixture to a serving dish, crumble feta over the top, and season with pepper and salt to taste.