In a small mixing bowl, stir refried beans and Rotel tomatoes together. Spread in the bottom of a 9x13" pan.
In a medium bowl, whisk together taco seasoning and Greek yogurt. Spread over the refried beans.
Mash the avocados to the consistency you like, and combine with lime juice and garlic salt. Spread over the yogurt layer.
Sprinkle the shredded cheddar cheese over the top, then sliced olives, then diced tomatoes, and last but not least - green onion. Chill for 30 minutes before serving.