How to Make It
Stir together sugar and 1 cup water in a medium saucepan over medium-high. Cook, stirring occasionally, until sugar has dissolved, about 4 minutes. Remove from heat and let cool completely. Chill for at least 1 hour.
Stir together pineapple juice, rum, Campari, lime juice, salt, and chilled simple syrup in a large bowl. Stir in Prosecco and ice cubes just before serving. Garnish with orange and lime slices.