Make the dip by combining the buttermilk ranch dressing, cucumber, milk, horseradish, wasabi, salt, and cayenne pepper into a blender. Blend on low until well mixed.
Pour into a small bowl and refrigerate. The dip will thicken as it chills.
Place the broth in a saucepan over medium-high heat.
Add the beans, cover, and bring to a boil; reduce heat to medium and simmer until beans are bright green and tender, about 8 minutes. Immediately drain beans into a colander and rinse under cold water. Set aside to cool.
Combine the beaten egg with milk in a shallow bowl.
Place the flour in another shallow bowl. In a third shallow bowl, combine the bread crumbs, salt, black pepper, garlic powder, and onion powder. Working with a handful of beans at a time, dip each bean first into flour, then into the egg mixture, and then into the bread crumb mixture.
Place beans on a plate until all are coated.
Heat 1 1/2 inches of oil in a deep skillet (or use a deep fat fryer) over medium-high heat to 350 degrees F (175 degrees C). Fry the beans several at a time, without crowding, until golden brown.
