To make rhubarb compote, combine rhubarb, sugar and lime juice in large skillet set over medium-high heat. Cook, stirring often, 12 to 15 min. until thickened to jam-like consistency. Cool slightly then refrigerate 1 hr. or until chilled through.
Whip cream with electric mixer until stiff peaks form. With rubber spatula, gently fold in mashed banana, rum (if using) and vanilla.
Divide whipped cream mixture among 4 (½ cup/ 125 mL) serving glasses. Top with rhubarb compote. Refrigerate at least 30 min. or up to 4 hr. Garnish with toasted coconut, if using, to serve.
To prepare fresh rhubarb, trim ends and discard leaves.