In a large mixing bowl, combine the ground beef, rice, grated onions, grated tomatoes, 1 tablespoon of tomato paste, red pepper flakes, dried mint, black pepper, cumin, and salt. Mix everything thoroughly until well combined.
Gently rinse the grape leaves under cold water to remove excess brine. Lay them flat on a clean surface, vein side up.
Place a tablespoon of the filling at the base of each grape leaf. Fold in the sides and roll tightly from the base to the tip, ensuring the filling is secure inside. Repeat this process until all leaves and filling are used.
In your pot or Dutch oven, drizzle a bit of sunflower oil on the bottom. Arrange the stuffed grape leaves seam side down in a circular pattern. If desired, you can layer the leftovers on top.
In a separate bowl, mix 2-3 cups of water with 1 tablespoon of tomato paste. Pour this mixture over the stuffed grape leaves until they are just covered. You may need to adjust the water amount based on the size of your pot. Place a plate on top of the dolmas to keep them submerged and simmer on low heat for 45-60 minutes.
Once cooked, remove from heat and let them cool slightly before serving. Drizzle with a little more sunflower oil and enjoy warm or at room temperature with a squeeze of lemon juice.