Summarize:

Place the cut eggplant on a baking sheet lined with paper towels and use a liberal amount of salt on the open side of the eggplant slices. Salting helps draw out the extra water, so the baked eggplant will turn out less watery and mushy. It also prevents the eggplant from soaking up too much oil. You can skip this step if you're in a hurry, but it's worth doing if you want the texture of your eggplant to turn out perfectly. As the salt sits on the eggplant slices, you will see droplets of water begin to bead and drip from the fruit. If you don't see this occurring, sprinkle more salt on the eggplant. Carefully squeeze the water into a bowl or the sink, then pat the eggplant slices with paper towels to absorb the excess moisture. Be careful not to squeeze too hard and crush the eggplant.
Sprinkle the sliced eggplant with kosher salt. Wait thirty minutes. Squeeze the saltwater from the eggplant slices.