Heat olive oil in a sauce pan over medium-high heat.
Add onion and sautee for 5 minutes, or until soft and translucent.
Add garlic and stir for 30 seconds - just until fragrant.
Add beans (with liquid) and taco seasoning.
Simmer for 15 minutes, stirring occasionally.
Serve warm.
Notes
Fats: Use olive oil or lard to thicken the beans and saturate the aromatics. These also help tenderize the beans.
Onions and Garlic: Add jalapeno for a spicy touch. You can also give the beans more flavor with cumin, salt and pepper, a squeeze of lime juice, Mexican oregano, cilantro, or a clove of minced garlic.