Run a lime wedge around the rim of each rocks glass. Dip the rim into a small plate of coarse salt and turn it to coat evenly. Fill each glass with fresh ice and set them aside.
Roll the limes on the counter to loosen the juice. Cut them in half and squeeze until you have 3 ounces. Strain out any seeds so the drink pours smooth.
Pour the cranberry juice, tequila, orange liqueur, and lime juice into a large pitcher. Stir well for about 20 seconds. The mixture should look deep red and smell citrusy.
For the best chill, pour one portion into a shaker with ice. Shake hard until the outside of the shaker feels frosty. This also adds a tiny bit of dilution that softens the alcohol.
Strain the shaken drink into a prepared glass over fresh ice. Take a quick sip to check the balance. Add a splash more lime if you want it tangier, or a little more tequila if you want it boozier.
Drop a few fresh cranberries into the glass. Tuck in a rosemary sprig or a lime wheel on the side. Serve right away while the glass is cold and the ice is crisp.