Rim margarita glasses with lime and dip in salt if desired.
Add tequila, orange liqueur, lime juice, agave syrup, and ice to blender. Blend until slushy.
Pour into glasses, top with ginger beer, and stir gently.
Garnish with a lime wheel and serve immediately.
Notes
Use less ice for a thinner drink, or more for extra slush. Adjust agave for sweetness. Add extra ginger beer for a bigger kick. For a non-alcoholic version, skip tequila and use more ginger beer and lime.