Unpack the jar of grape leaves. In a colander, place the grape leaves and rinse the brine using cold water. Set aside to drain excess water.
In a saucepan over medium heat, add 2 tablespoons olive oil. Next, add the onion and cook, stirring occasionally until softened, about 5 minutes. Add the scallion, and continue cooking until the onion is completely soft. Then, add rice and a pinch of salt, and stir constantly, for 2 minutes. Add half a cup of water and stir occasionally, for about 10 minutes.
Remove from the heat, and season with pepper. Set aside until fully cooled, then add the dill, mint, and parsley. Mix together.
Line the bottom of a large pot with 3 layers of grape leaves (this will prevent the leaves from scorching later).
Working one at a time, place the remaining leaves, vein, and bottom-sides up with the points facing away from you. Place a generous tablespoon of filling in the center of each leaf, then fold the left and right sides over the filling. Next, roll tightly to make a cigar shape. Place the roll, seam-side down in the lined pot. Continue in this order with the remaining leaves by filling and placing them tightly together in the pot.
Next, place the pot on the stove, and add 1 cup boiling water, the lemon juice, and the remaining olive oil. Place a plate on top of the leaves to prevent them from unraveling if needed. Bring to a simmer over medium heat, then lower the heat to medium to low, and cover the pan. Cook until the rice is tender, and the leaves are very tender, about 45 minutes.
Remove the pot and allow to cool. Serve the dolmades at room temperature or chilled. Drizzle with olive oil and include lemon wedges for squeezing and Greek yogurt.