In a large skillet, heat the olive oil over medium-high heat. Add the beef chunks and sear on all sides until browned. Remove from the skillet and set aside.

In the same skillet, add the chopped onion and sauté until translucent, about 5 minutes. Add the minced garlic and cook for an additional minute.

In a slow cooker, combine the seared beef, sautéed onion and garlic, cumin, oregano, smoked paprika, chili powder, cayenne pepper, diced tomatoes, beef broth, bay leaves, salt, and pepper. Stir to combine.

Cover and cook on low for 8 hours or high for 4 hours, until the beef is tender and easily shredded.

Once cooked, remove the beef from the slow cooker and shred it with two forks. Discard the bay leaves.

To serve, heat the corn tortillas in a dry skillet over medium heat until warm. Fill each tortilla with shredded beef, and top with chopped cilantro and diced onions. Serve with lime wedges on the side.