For the simple syrup:
In a small saucepan, combine the water with 100 g of sugar over medium heat. Bring to a boil and stir until all the sugar is dissolved. Take pan off heat and set aside to cool.
For the sugar rims:
In a shallow bowl, combine the remaining 50g of sugar with the lemon and lime zest. Rub the lemon around the glass rim, making sure to evenly coat both inside and out. Lightly press the rim into the sugar to frost.
In a small pitcher, combine the Prosecco, amaretto liqueur, lemon juice, and 2 tbsp of cooled simple syrup. Pour into the sugared glass over ice.
Garnish with a slice of lemon and a slice of lime.