For the beans:
For the rice:
Rinse the dried beans in a colander. Place them in a large bowl and add water to cover by an inch or two. Soak overnight. In a large pot, add the olive oil, onion, and garlic. Cook on medium heat until the onion is translucent, about 3 to 5 minutes. Drain the beans and add them to the onion mixture with the oregano and chicken stock. Bring to a boil. Add the vinegar and season with sea salt and pepper to taste. Cover and simmer over low heat for 1-3 hours or until beans are tender and cooked through. To store, let them cool completely and place the beans and all of their liquid in an airtight container. I think they are best the day after they are made, as the liquid thickens the flavors develop. Keep in the fridge for 4-5 days or freeze for up to 3 months.
While the beans are cooking, start preparing the rice. Place the olive oil and rice in a small pot. Turn the heat to medium and toast the rice for 1-2 minutes, stirring constantly so it doesn’t burn. Add the water, sea salt, black pepper and bring to a boil. Once boiling, lower the heat and cover, simmering for 20 minutes. Remove from the heat and allow rice to sit, covered, for 5-10 minutes. Fluff with a fork before serving with the beans. Serve the pinto beans over the rice with your garnishes of choice.