In a large skillet, brown the ground beef and onions over medium heat until meat is no longer pink; drain well.
Stir in the beans, one can of enchilada sauce and ½ cup salsa; set aside.
Top each tortilla with ⅔ cup beef mixture.
Roll up and place seam side down in two greased 9 x 13 inch baking dishes (8 enchiladas per pan).
Drizzle with the other can of enchilada sauce and remaining salsa.
Sprinkle with cheese and olives.
Bake uncovered for 20-25 minutes.
Notes
To use one of the pans as a freezer meal - cover well and place in the freezer. If frozen, remove enchiladas from freezer, leave foil on pan and cook for approximately 30 minutes. Remove foil and cook additional 15-20 min, until bubbling and cheese completely melted.