Spread the refried beans evenly in the dish.In a bowl, mix the taco seasoning and the sour cream, and spread it over the refried beans.Spread the salsa over the sour cream.Half, pit, and scoop the avocados into a bowl. Mash with a potato masher. Then spread over the sour cream.Continue layering the lettuce, Mexican cheese, and finally the tomatoes. Chill for at least an hour before serving.