Cut the limes in half from end to end. Juice each lime half to remove the liquid, (reserve the lime juice for another recipe). Using a cloth, pull the white fiber on the inside of each rind away from the peel to completely clean each lime half. If you are having trouble pulling the membrane out of the lime rinds, use a scissor to make a small cut right at the stem-point of the lime, on the inside, to get started.I found the peeling of this material away from the lime rind to be rather difficult, and ended up utilizing scissors and a melon baller to scrape, and a cloth to get a good hold to pull it out. Just be careful not to scrape through the peel.(See photos).
Transfer the clean lime haves to a muffin tin.
In a saucepan, add limeade. Sprinkle gelatin over the juice and let sit for 2 minutes. Next, gently heat the limeade on low, stirring, until the gelatin has dissolved, about 5 minutes.
Remove from heat, (liquid should be just warm, not hot), and stir in tequila, triple sec and sweetened lime juice. Pour the mixture into the lime halves.
Refrigerate until set, about four hours. When they are firm, turn each half upside down and gently cut in half to make wedges. I found using a serrated knife worked best for this.To serve, sprinkle with coarse salt.