Wash the pinto beans and strain them. Repeat. In a bowl, cover beans in water and let soak overnight. Drain.
In a pot, put water, beans, half the onion, a garlic clove, bay leaf and salt and cook on low heat for about 30 minutes, or until beans are just tender.
Transfer beans to a blender, with their liquid, and blend until smooth. Set aside.
In a frying pan, sauté the chicken with the rest of the onion and sliced garlic clove and season with a bit of salt and pepper, just until hot.
Heat tortillas using preferred method, (nonstick pan, directly over heat, castiron pan, etc.), then fill each one with a spoonful of chicken mixture and fold like a taco.
Pour the bean sauce over the top of the filled tortillas and garnish with cilantro, queso fresco, avocado and pickled red onions and serve.