Add the tequila, frozen orange juice concentrate, and the ice into your blender jar. Blend until you have a smooth and slushy consistency.
Serve:
Measure and pour ½ ounce of grenadine into a tall glass. Fill the glass a third of the way with frozen orange cocktail. Use a cocktail spoon to mix the grenadine into the frozen drink.
Fill the rest of the glass nearly to the top.
Garnish with an orange wedge and a maraschino cherry.