I loved licking a half lemon with salt on it when I was a child and these fermented or preserved lemons taste just like that. This recipe is a Near Eastern process and they use it for many recipes but I just like eating them right out of the jar. The rinds get softer with time.
To a 1 ( wide mouth) or 2 quart jar, add some fresh lemons that are cut up into quarters or 8ths and seed them, if you want, as you go. With your fist, or some other tool that fits, press them down to bring up the juice. If not enough juice, add 1-2 TBS chlorinated water. To each quart add 2 TBS Real Salt as you go. When filled to the neck of the bottle, where it slopes in, press hard again to bring up the juice. Attach an air lock device to the top and ferment for about 5 days. Then, remove the air lock and secure a regular lid and put in refrigeration for a week.
After that, date and store in cool, dry, dark place or start eating them. You might try researching "preserved lemons" to get some recipes on how to use them .