In Slow Cooker, Combine Boiled Pinto Beans With Bouillon Cubes And Enough Water To Almost Fill Cooker. Let Simmer On Low Setting For 8 Hours. In A Large Skillet, Brown Beef With Salt, Pepper And Onion. Drain Well And Set Aside. Assemble As Follows: Top Each Tortilla With Beef Mixture, Cheese And A Ladel Of Beans With Juice From Slow Cooker. Top With Preferred Garnishes As Desired And Serve.