This is how my husband's family does tostadas. You can easily make a "something for everyone" meal out of it, by offering Tacos or Tostadas.
1 lb ground beef (or meat of choice)
1 can refried beans
Brown beef, and drain. Season with taco seasoning. Mix in refried beans. Layer chips on the bottom, with meat mixture on top. Then, add whatever toppings you would like.
You can also leave the meat and refried beans seperate. Serve tortillas or taco shells, and let everyone choose what they would like.