Season the beef bottom round roast on all sides with the sea salt, black pepper, ground cumin, and smoked paprika.
Heat the extra virgin olive oil in a large skillet over medium-high heat and sear the beef for 3-4 minutes per side until a deep golden-brown crust forms.
Transfer the seared beef roast into the basin of your slow cooker.
In the same skillet used for the beef, add the diced yellow onion and sauté for 3 minutes until softened, then add the minced garlic and cook for 1 additional minute.
Stir in the tomato paste and minced chipotle peppers, cooking for 2 minutes to allow the sugars to caramelize and the flavors to concentrate.
Pour the beef bone broth into the skillet to deglaze, using a wooden spoon to scrape up all the flavorful browned bits from the bottom of the pan.
Pour the onion and chipotle liquid mixture over the beef in the slow cooker.
Cover the slow cooker and cook on the low setting for 7 to 8 hours, or on high for 4 hours, until the beef is tender enough to shred easily.
Remove the beef from the slow cooker and use two forks to shred the meat into thin ribbons, then return the shredded beef to the pot to soak up the remaining sauce.
Garnish the shredded beef with fresh chopped cilantro before serving.