In a large saucepan, heat the oil over medium heat.
Add the onion and cook, stirring, for 4-5 minutes until soft.
Add the garlic and cook for another minute until fragrant.
Stir in the vegetable broth, tomato paste, dried oregano (if using), and adobo sauce until combined.
Add the rinsed kidney beans and use a potato masher or the back of a spoon to gently mash about a quarter of the beans against the side of the pot to thicken the stew.
Bring the mixture to a boil, then reduce the heat to a simmer.
Cook, uncovered, for 5 minutes, stirring occasionally.
Remove from heat, stir in the fresh cilantro and fresh oregano (if using), and serve hot over brown rice with fresh lime wedges.