If your dates are still hard, soak them in hot water for a few minutes to soften, then thoroughly pat dry before chopping them for the salad.
Place a rack in center of oven; preheat to 450°F. In a medium bowl, toss carrots with 1 Tbsp. oil, 1/2 tsp. salt and 1/4 tsp. pepper. Arrange in a flat layer on a large baking sheet. Roast, stirring occasionally, until golden brown in spots and tender, about 20 minutes.
Rub kale with remaining 1/2 tsp. salt and 1 Tbsp. lemon juice until softened. Divide among 4 plates. Whisk together mustard, honey and remaining 1/4 tsp. pepper and 2 Tbsp. lemon juice. Slowly whisk in remaining 2 Tbsp. oil.
Top kale with roasted carrots. Drizzle with dressing and sprinkle with dates and cheese. Season with additional pepper, if desired, and serve.