Put peeled, sliced eggplant into a crock pot, with a thin layer of salt between layers. Weigh it down with a heavy bowl or plate between layers, and a heavy jar (such as olive oil) on top of that, and let it sit a few hours.
Squeeze all water out and drain, then squeeze and drain again. Cut into thin strips like matchsticks.
Put eggplant in a bowl and pour vinegar over it. Leave about 5-10 minutes until eggplant turns white. Take out of vinegar and squeeze.
In a large bowl, mix eggplant, pepper, garlic, and oregano.
Put eggplant mixture in jars, leaving about an inch on the top, and fill with oil. Keep checking that the eggplant is covered with oil.
Make sure the bubbles have come to the top before covering the jar. Cover jars and let sit 24 hours before serving.