In a small bowl, add finely chopped onion to a small bowl and add about ½ cup cold water. Allow onions to soak while you prep other ingredients.
In a large bowl, combine peas, eggs, peppers, and cheese. Add onions after they’ve soaked, then toss ingredients together.
In a small bowl, whisk together all dressing ingredients.
Pour dressing over salad and toss until fully coated.
Cover and chill for at least 30 minutes before serving.