To make salted sunflower seeds while the seeds are still in the shell, soak the seeds in salted water, and bake them in the oven. Toasting of the outer shell can be done before removing them from the oven to be sure they are roasted enough.
When soaking the sunflower seeds, use 1/4 to 1/2 cup of salt for every 2 quarts of water. Place the seeds in the salted water overnight. This lets the salt reach the inside of the shells. In the morning, drain the water and place the seeds on a paper towel to remove the moisture. This is enough to get them salted, but roasting is often recommended. To roast them, preheat the oven to 300 degrees Fahrenheit, and place the seeds on a cookie sheet in a single layer. Roast them for 30-40 minutes or until golden brown.