The key to make these super delicious is to use frosty glasses! So a few hours (or the night) before, stick your glasses in the freezer. I suggest making a single serving first and taste it so you can add more/less tequila or syrup to your liking. Everyone is different and prefers their drinks a different way, so feel free to add more or less tequila, more simple syrup, more lime juice, etc. This is my absolute favorite combo listed above.
Before serving, rim the edge of the glass with a lime slice and then dip it in coarse salt to coat. Fill the glass with just a few ice cubes or even with crushed ice – my ice preference of late.
In a shaker, combine the lime juice, beer, tequila, grand marnier and simple syrup. Shake well for 30 seconds, then pour it over the crushed ice. Garnish with the extra limes.