In a large pot over medium heat, warm the oil. When oil is warm add in onions and begin to saute.
Once onions are softened add in beans and taco seasoning. Stir ingredients to mix well.
Then add in the diced tomatoes and 3 cups of water to the pot. Turn up the heat, working towards a boil.
Add in spaghetti, wait for liquid to start boiling. When you get a boil, reduce the heat, cover with a lid and wait 10 minutes. At the 8 minute mark, you can take off the lid to stir to help avoid sticking on the bottom of the pan.
After 10 minutes if there is still liquid left, you can remove the liquid and continue to cook for another 2 minutes or until standing liquid is cooked off. The pasta should look creamy and delicious.
Plate pasta and garnish with tomato, black olives and cilantro.