Eggplant is full of water. When it sits salted for awhile, the moisture is extracted, resulting in a firmer eggplant. Cut the ends of the eggplant away. (You can either peel it or not; some say the skin is bitter, but I haven't found this to be true.) Slice into rounds; then cut into 1/4" inch cubes Place a paper towel in a collander; add eggplant, season generously with salt; lightly toss then cover with a dish towel. (This is to reduce oxygenization, which causes the eggplant to turn brown.) Let it sit while you prep the other vegetables. When it's time to saute the eggplant, pour it onto a dry paper towel and pat gently. Some of the salt will come off and that's okay.