For Garnish: Combine sugar and cocoa powder in small bowl. Coat rim of serving glass with simple syrup, then sprinkle with 1/2 tsp. sugar mixture; set aside.
For Daiquiri: Combine all Daiquiri ingredients, except OREO Pieces, in blender container. Blend until smooth. Add OREO Pieces and pulse 5 seconds. Pour into prepared glass. Garnish with 1/2 oz. whipped cream piped using pastry bag fitted with star tip, and 1 banana slice dusted with OREO Small Cookie Pieces.