Optional: For a salt rim, cut a notch in a lime wedge, then run the lime around the rim of a glass. Dip the edge of the rim into a plate of salt.
Add the tequila and ice to a glass and stir to combine.
Top with the cola. Squeeze in the juice from the lime wedge (or the 1/2 ounce lime juice) and serve. Garnish with additional lime wedges or wheels if desired.