Have ready 4 tall glasses or tumblers. Spread the salt and chili powder on a small, flat plate. Cut 2 of the limes into 4 wedges each. Run 1 lime wedge around the rim of each glass to moisten it, then dip the rim into the chile salt to coat it evenly. Reserve the remaining 4 lime wedges for garnish.
Juice the remaining 4 limes; you should have about