1 red grapefruit, peel and pith removed
1 navel orange, peel and pith removed
3 tablespoons freshly squeezed lime juice
4 1/2 teaspoons finely chopped fresh cilantro, plus leaves for garnish
1/4 teaspoon crushed red pepper flakes
1/4 teaspoon coarse salt
1 small jicama, (about 1 1/4 pounds), peeled and cut into thin matchsticks
1 medium Granny Smith apple, cut into 3/4-inch chunks
1 Kirby cucumber, peeled and cut crosswise into 1/4-inch-thick rounds
Working over a large bowl, carefully carve out sections of grapefruit and orange from membranes using a paring knife, letting sections fall into bowl and reserving membranes.
Transfer juices to a small non-reactive bowl; squeeze membranes into bowl.
Add lime juice, cilantro, red pepper flakes, and
salt to the small bowl with the juices; stir to combine.
Add jicama, apple, and cucumber to the large bowl with the fruit.
Pour juice mixture over fruit mixture.
Gently toss to coat.
Let salad stand for 10 minutes before serving.