Chop onion, and saute in a pan heat with oil, for 3 to 5 minutes or until onion is translucent.
Stir in the beans. Wait 1 minute then shut off heat.
In another pan slightly heat the tortillas.
Assemble your taco and enjoy with your favorite chili or sauce.

4 tortillas
1 can refried beans
1/2 onion
1 tablespoon vegetable oil