Dice the tomatoes into medium-sized chunks, being sure to capture all the flavorful juices.
In a large bowl, combine the mayonnaise, apple cider vinegar, sugar, salt, pepper, and garlic powder if using. Whisk until smooth and creamy.
Add the diced tomatoes, sliced green onions, and chopped hard-boiled eggs to the dressing. Gently fold everything together until evenly coated.
Just before serving, add the crushed saltine crackers to the mixture. Stir gently but quickly to incorporate them throughout the salad.
Cover the salad and refrigerate for about 30 minutes before serving to allow the flavors to meld together.
Garnish with fresh parsley just before serving.