For the marinade:
1/3 cup extra virgin olive oil
2 tablespoons tarragon vinegar
1 tablespoon Creole mustard
½ teaspoon Worcestershire sauce
1 garlic clove, minced
¼ teaspoon dried oregano
Fill a large bowl with ice water and set aside. Place a steaming basket inside a large saucepan with 1” of water and bring to a low boil. Add green beans and carrot sticks to steaming basket. Cover and cook until beans and carrots are cooked through but still have a slight crunch. Remove from steaming basket and immediately immerse in the ice water bath until cool. Remove from water and pat dry.
In a large mixing bowl, whisk together all marinade ingredients. Add green beans, carrots, onions, black olives, cucumber and cherry tomatoes. Toss to coat. Refrigerate until ready to serve.