On a small plate combine kosher salt and toasted sesame seeds (if using). Run the cut edge of a lime wedge around the outer rim of a rocks or coupe glass, then dip the rim into the salt-sesame mixture to coat. Set the glass aside.

Chill glass

Place the rimmed glass in the freezer or fill it with ice water to chill while you mix the cocktail.

Make cocktail

Add the reposado tequila, Cointreau, fresh lime juice, yuzu juice, agave syrup, and the dash of saline into a cocktail shaker.

Fill the shaker with ice (about 3/4 full or roughly 1 cup). Secure the lid and shake vigorously for 12–15 seconds until the outside of the shaker is frosty and the ingredients are well chilled and slightly diluted.

Discard the ice or water from the chilled glass. Double-strain the cocktail into the prepared glass (use a Hawthorne strainer and a fine mesh strainer if available) over fresh ice if serving on the rocks, or without ice if serving straight up.

Garnish with a lime wheel or wedge on the rim. Optional: express a lime peel over the drink and drop it in for aroma.

Serve

Serve immediately. Sip and enjoy the interplay of tequila, citrus (lime + yuzu), gentle sweetness from agave, bright orange notes from Cointreau and the savory accent from the salted sesame rim.