Rub lime juice around the rim of a rocks glass (or shot glass). Pour a chili seasoning mix like tajin, or kosher salt on a small plate. Repeat with all glasses
Add the jalapeno slices to a cocktail shaker or pitcher and gently muddle to release the oils.
Add the tequila, orange liqueur, lime juice, and agave nectar or simple syrup to the pitcher. Stir to thoroughly combine.
Strain margaritas into prepared glasses, or shot glasses, filled with fresh ice. Garnish with jalapeno slices and lime wheel. Serve immediately.
Notes
This pitcher of spicy jalapeno margaritas makes approximately 32 ounces. Choose the size of your pitcher accordingly.
The serving is approximately 4.5 ounces + the ice, which is 7 standard servings. Using shot glasses will allow you to serve more.