Grapefruit-Blackberry Dressing

1/4 cup olive oil
1/2 cup fresh-squeezed grapefruit juice
1/4 cup whole-fruit blackberry preserves
Arugula
Mango
Jicama, cubed

Whisk together olive oil, fresh-squeezed grapefruit juice, and whole-fruit blackberry preserves; serve over a salad of arugula leaves, mango and jicama cubes, blackberries, and grapefruit sections.