Spray the bottom and sides of a slow-cooker crock with non-stick cooking spray.
In the slow cooker crock, add the tomatoes, beef stock, lime juice, onion, jalapeno, and spices. Stir to combine.
Brown the meat on all sides in a large skillet over medium-high heat. Transfer the meat to the crock pot and nestle it into the sauce. Cover and cook on low for 8 hours.
When done cooking, remove lid and shred beef with two forks while still inside the slow cooker. Allow shredded beef to marinate in warm cooking juices for at least 5 minutes to absorb more flavor.
Transfer shredded beef with tongs from the slow cooker to a fine mesh strainer and allow excess liquid to drain. Then transfer it to a serving platter or bowl. Top with chopped cilantro and serve immediately with cilantro and fresh lime wedges.