Commercial sunflower seeds are hulled by large high-volume machinery, which is well beyond the budget of a home gardener or small farmer. But it's useful to have a method of hulling seeds in small numbers for personal use -- and there are various ways to go about it, depending on frequency and quantity.
The simplest method of hulling sunflower seeds is to spread them in a single layer on a counter or other work surface and roll them with a heavy rolling pin. Most other methods of crushing the shells are prone to crushing the seeds as well, but the downward pressure of the rolling pin can be adjusted as needed. Once the hulls are crushed, scoop the seeds into a flat basket and take them outdoors on a windy day or set them in front of a powerful fan. The seeds will remain in the basket, the hulls will blow away.
Between the Sheets
Another simple method of hulling sunflower seeds is to place them between two nested baking sheets and walk on the upper sheet. The results are not as consistent as with the rolling pin method, but it's an entertaining rainy-day activity for youngsters. Separate the sheets and remove the empty hulls using the wind or a fan. Return the intact seeds to the sheets for another batch.
Hand-Operated Grain Mill
Hand-operated grain mills are on the market for grinding flour or flaking breakfast cereal at home. With a bit of attention to the settings, it's possible to hull sunflower seeds with most models. Simply fill the hopper with seeds and adjust the grinder's spacing until it cracks the hulls. For best results, the seeds should be presorted for size. The hulls must still be winnowed from the seeds with wind or a fan.
Motorized Grain Mill
For anyone processing small batches of seeds on a regular basis, motorized grain mills make good sense. They are very similar to hand-operated versions and will hull the seeds just as gently. The major difference is that motorized mills tend to have large feed hoppers, allowing for big batches. There can be a significant difference in cost between motorized and hand-operated mills, so casual users might prefer the manual variety.