In a large bowl, combine the rice, green onions, 1 tablespoon of the lemon juice, lemon zest, dillweed, about 1⁄2 teaspoon of salt (less if your rice is well seasoned), and freshly-ground black pepper. Add some ground cayenne if desired. Mix well.

Trim the stems from the grape leaves. Place one grape leaf at a time on a work surface, shiny side down. Place about 1 tablespoon of the rice mixture near the stem end and fold the sides of the leaf over the filling. Beginning at the stem end, roll up the leaf firmly into a neat roll. Repeat with the remaining ingredients.

Place the stuffed leaves in a large skillet. Add the oil, remaining 2 tablespoons lemon juice, and just enough water to come about halfway up the stuffed leaves. Cover and heat to a simmer.

Cook over low heat until tender, 20 to 30 minutes. Uncover, remove from the heat, and set aside to cool.

Use a slotted spoon to transfer to a platter. Serve at room temperature.