Grab enough limes to make an ample amount of juice (approx 5-6 = 1 cup). Halve and juice the limes, setting aside a small sliver of one for later. Pour the lime juice into a drink pitcher. Add your tequila, triple sec and guava juice (canned is fine for this part) to the pitcher, and mix.

Next, fill a chilled cocktail shaker halfway with crushed ice and pour the desired drink amount from pitcher; cover and shake vigorously. Pour enough sea salt onto a plate to cover in one thin layer. Moisten rim of cocktail glass with a lime wedge and place rim-down in the salt, twisting glass to coat the rim. Turn the glass back over, add a few cubes of ice, and pour drink from shaker into glass. Voila!