If drinking margaritas right away, rub a cut lime around the rim of the jars and dip rims in margarita salt. Garnish with a sliced lime.
If making ahead, pour blended margaritas into half-pint jars. Make sure to leave some space for the margarita to expand when freezing. Screw on lids and freeze. To serve, remove from freezer and immediately rub jar rim with a sliced lime and dip in margarita salt while the margarita is still frozen solid so it won’t spill out of the jar. Leave jars out for a few minutes to thaw and use a fork to break up any frozen chunks and stir.