Combine cranberries, sugar, water, and orange zest in a small saucepan. Bring to a gentle boil over medium heat, causing the cranberries to start burst and release their juice, filling your kitchen with a bright citrus aroma.
Reduce the heat to low and let the mixture simmer for about 10 minutes, stirring occasionally, until the cranberries soften and the syrup thickens slightly. The syrup will turn a deep ruby red and smell tart and citrusy.
Pour the mixture through a fine sieve into a bowl, pressing gently to extract as much flavorful syrup as possible. Discard the solids and allow the syrup to cool to room temperature.
Meanwhile, prepare your flute glasses by placing a few fresh cranberries and a twist of orange peel inside for a festive look and aroma.
Once the cranberry syrup has cooled, add about 2 tablespoons to each flute glass, then slowly pour in 4 ounces chilled sparkling wine, pouring gently to preserve the bubbles and avoid overflowing.
Garnish each drink with a fresh cranberry and a twist of orange peel for visual flair and extra aroma. Serve immediately with a light clink of glasses and enjoy the lively, tart celebration in a glass.