Preheat your oven to 300°F (150°C).
In a small bowl, whisk together the smoked paprika, garlic powder, onion powder, sea salt, and black pepper to create a dry rub.
Rub the beef brisket evenly with the olive oil, then coat all sides thoroughly with the prepared spice mixture.
Place the brisket in a heavy-bottomed baking dish or Dutch oven, cover tightly with foil or a lid, and roast for 3 to 4 hours until the meat is tender and easily pierced with a fork.
While the meat rests, combine the tomato paste, apple cider vinegar, maple syrup, and liquid smoke in a small saucepan over low heat, whisking until smooth and slightly thickened.
Remove the foil from the brisket, brush the BBQ glaze generously over the top, and place under the broiler for 3-5 minutes until the glaze is bubbling and slightly charred.
Steam the green beans until tender-crisp, slice the brisket against the grain, and serve immediately.