Preheat your smoker or oven to 225°F (107°C).
In a small bowl, combine the sea salt, black pepper, smoked paprika, and garlic powder to create a dry rub.
Pat the brisket dry with paper towels and apply the dry rub evenly to all sides of the meat.
Place the brisket in the smoker or oven and cook until the internal temperature reaches 195°F (90°C), which typically takes several hours depending on thickness.
While the brisket cooks, whisk together the tomato paste, apple cider vinegar, and maple syrup in a small saucepan over low heat to create the BBQ glaze.
During the last 30 minutes of cooking, brush the glaze generously over the top of the brisket.
Toss the green beans with olive oil and onion powder, then roast at 400°F (200°C) for 12-15 minutes until tender-crisp.
Remove the brisket from the heat and let it rest for at least 15 minutes before slicing against the grain to serve.