How to Make It
Prepare the Grapefruit Simple Syrup: Combine sugar, water, and grapefruit zest in a small saucepan. Cook over high, whisking occasionally, until sugar dissolves, 4 to 5 minutes. Remove from heat, and let stand 15 minutes. Pour mixture through a fine wire-mesh strainer into a bowl; discard rind. Cover and chill syrup until ready to use.
Prepare the Paloma: Stir together grapefruit juice, tequila, syrup, and lime juice in a pitcher. (Reserve remaining Grapefruit Simple Syrup for another use.) Pour evenly into tall glasses filled with ice. Top with soda water. Garnish with grapefruit peel twists.