Create dressing: In a small bowl, combine lemon juice, paprika, and cumin. While whisking, slowly drizzle in olive oil to emulsify. Season with salt and pepper to taste.Dress the kale: In a large bowl, drizzle chopped kale with dressing. Massage dressing into kale leaves until well-coated, 3 to 5 minutes. (At this point, kale can be refrigerated overnight.)Assemble salad: Add radish, onion, and tomatoes to salad and toss to combine.