In a medium bowl, combine the refried beans, chili powder, cumin, 2 teaspoons salt, ground black pepper, paprika, garlic powder, onion powder, and dried oregano. Mix well and set aside.

In a second medium bowl, mash the avocados with a fork or a potato masher to your desired consistency. Stir in the cilantro, lime juice, and 1 teaspoon salt.

In a 9x13-inch casserole dish, spread the refried bean mixture in an even layer. Follow with layers of guacamole, vegan sour cream, lettuce, tomatoes, black olives, and green onions.

Cover with plastic wrap and refrigerate for 1 hour. Serve chilled or at room temperature.