Coarsely chop 6 pineapple rings. Place in large bowl. Add sweetened condensed milk, lime rind and juice.
Divide pineapple mixture into 12 mini-tart shells. Cover; chill 2 hours.
To serve, cut remaining pineapple slices into thirds. Peel kiwifruit. Slice in half lengthwise; then cut each half crosswise into 6 slices. Garnish each tart with pineapple, kiwifruit and grapefruit. Garnish with fresh mint if desired. Makes 12 tartlets.
