Combine the refried beans, rotel diced tomatoes and taco seasoning in a bowl and whisk until combined.
Spread into an even layer in a 7"x11" casserole dish.
In a separate bowl combine the avocado, lime juice, cilantro and garlic salt. Mash together until a smooth consistency and spread into an even layer over the beans.
Stir the sour cream well and spread evenly over the guacamole.
Sprinkle the shredded cheese over the top of the sour cream, then top with the diced tomatoes, black olives and green onions.
Cover with plastic wrap and keep chilled until ready to serve.