Start by prepping your glass. Run a lime, pineapple, or jalapeno (spiciest) slice around half the rim of the glass. Dip in kosher salt. Now fill the glass half way with crushed ice.
Place a few cubes of ice in a cocktail shaker, add the tequila, Cointreau, lime juice, pineapple juice and 1-2 jalapeno slices. Shake vigorously for 20-30 seconds. Pro Tip: For more spice/heat start by muddling the jalapeno in the glass. For less spice/heat do not add the jalapeno slice to the shaker, just drop it in the margarita after straining it in the serving glass.
Strain the margarita into your prepared glass.
Garnish with a lime wheel, pineapple wedge, and/or a jalapeno slice.