Turkey Avocado Grinder Sandwich

Name: Turkey Avocado Grinder Sandwich
Prep time: 10 min
Cook time: 5 min
Total time: 15 min
Cuisine: American
Ingredients: 1/2 cup mayonnaise; 2 tablespoons white balsamic vinegar; 1 tablespoon extra virgin olive oil; 1 teaspoon Dijon mustard; 1 clove garlic (minced or pressed); 1 teaspoon dried oregano; 1/2 teaspoon kosher salt; 1/2 teaspoon black pepper; 1/2 medium red onion (thinly sliced); 1/2 cup cucumber (sliced); 1/4 cup black olives (sliced); 4 cups iceberg lettuce (sliced); 2 ciabatta rolls (sliced in half); 4 slices white cheddar cheese; 6 slices deli turkey; 1 avocado (sliced)