Add the sweet potatoes to a large pot of cold salted water. Bring to a boil over medium-high heat and cook the potatoes until tender, about 15 minutes. Drain the potatoes and let cool in a colander.
Once the potatoes are cool, transfer to a large serving bowl and add the onion, red pepper, and green onions.
In a separate bowl, add the mayonnaise, orange juice, smoked paprika, cumin and salt and pepper, to taste. Whisk to combine, pour over the potatoes and thoroughly mix. Serve immediately or refrigerate for 1 hour for the flavors to meld.