In a small bowl or a measuring cup, combine all the dressing ingredients: the olive oil, apple cider vinegar, lime or lemon juice, sugar, salt, black pepper, dried oregano, garlic powder, and red pepper flakes (if using).

Whisk the mixture vigorously until the sugar and salt have dissolved and the dressing is well-emulsified (looks slightly creamy). Alternatively, you can place all dressing ingredients in a jar with a tight-fitting lid and shake well.

In a very large mixing bowl, combine the rinsed and drained black eyed peas, the diced red bell pepper, the diced green bell pepper, the finely chopped red onion, the thawed sweet corn, the chopped parsley, and the diced tomatoes (if using). Ensure all vegetables are diced uniformly.

Pour the prepared dressing evenly over the salad ingredients in the large bowl.

Gently toss the ingredients together using large spoons or spatulas until everything is thoroughly coated with the dressing. Take care not to mash the black eyed peas.

Taste the salad and adjust the seasoning if necessary (add more salt, pepper, or a splash more vinegar for tang).

Cover the bowl tightly with plastic wrap and transfer it to the refrigerator. Allow the salad to chill for a minimum of 30 minutes, but ideally for 2 to 4 hours. This chilling time allows the flavors to fully meld together.

Just before serving, give the salad one final gentle toss. Serve chilled as a side dish, an appetizer with tortilla chips, or as a healthy lunch.