Combine 2 cups of water, salt, ginger, sugar, and red pepper flakes in a pan over the stove.
Bring the mixture to a boil and then reduce the heat and let it simmer for 10 minutes.
Remove the pan from heat and let it sit, covered, until it is cool.
Strain the syrup into a jar and put it in the fridge to chill.
Fill a tall glass with ice.
Put 2 Tbsp. of the spicy-ginger syrup and a lemon wedge into a glass.
Fill the glass with Tequila Chamucos and top with seltzer water and stir.