Place 2-4 pounds ripe, black olives in a basket or large colander, sprinkling generously with coarse sea salt. Place in a cool corner of the kitchen, over a large bowl. Shake and toss the olives at least once a day – more often if possible.
After 2-3 days, they will start to wrinkle and let out some of their juices. Keep tossing for at least another 3-4 days. Check if they are done by slashing one or two olives and checking the color of their inner flesh. If dark all the way to the pit, they are done. Let dry completely on paper towels, then rub with olive oil and sprinkle with herbs (dried oregano, savory, or thyme).
Let stand 1-2 days covered, before serving. To store, place in Ziploc bags or vacuum packs, and keep in the freezer. The very salty commercial ‘throumbes’ (dry-cured olives) keep long at room temperature, or in the refrigerator.