In a small bowl, add the salt and lime zest; stir until well combined.

Using a cocktail shaker, add the tequila and sliced jalapenos. Let sit for ~20 minutes. (Note: The longer this sits, the spicier the margarita will become.)

Strain out the jalapeno slices, reserving to use as a garnish later.

Add Grand Marnier, lime juice and agave nectar to shaker. Shake until well blended; set aside.

Place Lime Salt in a shallow bowl. Dip rims of cocktail glasses in water and then invert into bowl. Turn glasses right-side up and fill with ice.

Pour margaritas into glasses. Drop sliced jalapenos into margarita; garnish rims with sliced limes.