Wash and dry all produce. Preheat oven to 450°F. Cut sweet potato into ½-inch cubes. Toss on a baking sheet with 2 Tbsp. cajun spice blend, a drizzle of olive oil, and a pinch of salt and pepper. Roast in oven until lightly browned, about 25 minutes, tossing halfway through.
Meanwhile, drain and rinse corn. Halve, peel, and finely dice half the onion. Zest a small portion of the lime, about 1 or 2 strips and then halve lime. Halve the tomatoes lengthwise. Finely chop parsley. Drain and rinse beans.
Heat a drizzle of olive oil in a large pan over medium-high heat. Add corn and onion and cook until softened, 2-3 minutes, tossing. Season with salt and pepper.
Add beans and tomatoes to pan. Toss until heated through, about 1 minute. Season with salt and pepper. Transfer to a large bowl. Stir in lime zest and juice from lime.
When sweet potato is done roasting, transfer to large bowl with corn mixture and add feta, and half the parsley. Toss to combine. Season with salt and pepper.
Divide salad between bowls. Garnish with remaining parsley and serve.