This is a delicious way for me to sneak more fruit and vegetables into our family dinners. More than a 15-minute side dish, this can be dressed this up by spooning it into a radicchio-leaf cup for a first course, complement the next batch of salmon fillets or steaks off the grill, or taken along on your next picnic.
Whisk the olive oil, vinegar, and cilantro together in a large bowl until blended. Season lightly with salt and pepper. Add the beans, mango, jicama, and onion and toss gently to coat with the dressing. Season with salt and pepper, to taste. Serve right away or let stand at room temperature for up to 30 minutes. Toss and check the seasoning before serving.
If you can't find jicama, which adds an apple-y note to the salad, substitute a large green apple. Core the apple, leave the skin on, and dice it as you would the jicama.