Add the sumac and salt together, mixing to combine, then pour into a plate.
Using a lowball glass, rub the outer side of the glass with a lime half, then roll into the salt on the side. Add ice to fill, then add the juices, and tequila alternative. Stir till combined. You could also use a cocktail shaker if you have one. Fill to the top with sparkling water and stir again.
Margarita without lime (low histamine)
Using a lowball glass, use a paper towel to add a little bit of juice to the side then roll into the salt on the side. Add ice to fill, then add 1/3 cup mango juice and tequila alternative. Mix in 1/8 teaspoon of citric acid or 1/2 teaspoon of white vinegar. Stir till combined. You could also use a cocktail shaker if you have one. Fill to the top with sparkling water and stir again.
Spicy Margarita
Using a lowball glass, use a paper towel to add a little bit of juice to the side or rub with a lime half, then roll into the salt on the side. Add 2-3 jalapeño slices to the bottom of the glass. Fill with ice, then add the juices and tequila alternative. Stir till combined, using the spoon to smash some of the jalapeño. The more you smash the pepper and include seeds, the spicer it will be. You could also use a cocktail shaker if you have one. Fill to the top with sparkling water and stir again.
Notes
100% mango juice is the best but can be hard to find. Can be found at Sprouts or Trader Joe's. Sanzo sparkling mango is a great substitute, or you can use other types of juices like pineapple, pomegranate, or watermelon. Sub orange juice for a more classic margarita.
Coconut water - This will have less of that classic margarita flavor, but still tastes great and turns this into an electrolyte-rich mocktail. Great for hydration!
I find topo chico or gerolsteiner to be the best sparkling water for this because of the extra carbonation. Club soda can also be used.
Tequila alternative notes - For a spicy flavor profile, try Ritual tequila alternative. For a more classic flavor profile, try Seedlip.
For low histamine/HYH - Use all mango juice, and lime alternatives (or omit the citrus completely).