Place the sweet potatoes in a large saucepan and cover with water.
Bring to a boil and immediately reduce to a simmer. Cook the potatoes for 15-20 minutes until fork-tender. Drain the potatoes, place in a large mixing bowl and cool to room temperature.
In a small bowl, combine the yogurt, cilantro, lime juice, lemon juice and cumin. Add the yogurt mixture to the sweet potatoes then add the red onion, celery and jalapeno pepper. Toss until combined. Cover and refrigerate for 1 hour.
Place in a serving bowl and enjoy!