Preheat the oven to 400 degrees.
Cut zucchinis in half lengthwise and carefully scoop out the centers with a spoon, being careful not to break through the skin. Roughly chop the scooped out zucchini flesh and set aside. Place the hollowed zucchini halves into a baking dish.
Add the olive oil to a medium sauté pan over medium heat. Add the onions to the pan and cook for 3-4 minutes until they begin to soften. Add the garlic to the pan and cook for another 1-2 minutes then add the roughly chopped zucchini and cook until softened. Add the ground beef to the pan and cook, breaking apart with a wooden spoon, until well browned, around 8-10 minutes. Add the cumin, dried mint, salt and pepper and stir well to combine. Remove the pan from the heat and stir in the cauliflower rice and fresh dill.
Spoon the filling into the hollowed zucchinis, mounding them high and then drizzle with additional olive oil. Cover the baking dish with parchment lined baking foil and cook for 25-30 minutes. Zucchini should be tender and pierced easily with a knife but not mushy and falling apart. Garnish with additional fresh dill.