Line a large baking sheet with aluminum foil. Stir together sweet potatoes, corn kernels, 2 tablespoons of the oil, 1 teaspoon of the salt, and ½ teaspoon of the black pepper in a large bowl. Spread in an even layer on prepared baking sheet.
Bake until vegetables are tender, about 30 minutes.
Whisk together lime juice, honey, and remaining 1 tablespoon oil, ½ teaspoon salt, and ¼ teaspoon black pepper in a large bowl until combined.
Add sweet potato mixture, beans, and jalapeños to lime juice mixture. Stir until evenly coated.
Cover with plastic wrap, and refrigerate until completely chilled, at least 1 hour or up to 12 hours.
Add cilantro to salad. Toss to combine. Garnish with scallions, and serve.