Pour the salt into a shallow dish. Rim 6-8 lowball glasses with a lime wedge and dip into the kosher salt.
In a large pitcher add the tequila, lime juice, Cointreau, and agave to taste, and stir for 30 seconds. (Note: the agave nectar is totally to your preference! Some days I like a sweeter margarita and put the full cup of agave and other days I only like a small amount. Start out with 1⁄2 cup and taste test your way up.)
Place the margarita batch into the fridge for 1-2 hours before serving or fill glasses with crushed ice. Garnish with lime wedges and serve.