Preheat oven to 425 degrees F. Thinly slice two and half oranges. Zest one orange; set zest aside. Juice zested orange and remaining one and a half oranges. You will get about 2/3 cup juice. Set aside 1/3 cup for dressing. (Use the remaining 1/3 cup to toss with carrots in Step 2.)
Line a large roasting pan with foil. In a large bowl combine orange slices and 1/3 cup juice, the carrots, 1 Tbsp. olive oil, and 1/2 tsp. salt; toss to coat. Transfer to pan. Roast 20 minutes. Gently turn carrots and oranges. Roast 20 minutes more or until carrots are just tender and light brown.
Meanwhile, for dressing: In a small food processor or blender combine dates and the water. Cover; pulse until nearly smooth. Add orange zest and reserved 1/3 cup juice, remaining 2 Tbsp. olive oil, the vinegar, paprika, chipotle chile pepper, salt, and black pepper; set aside. Cover; process to combine. To serve, drizzle carrots and oranges with half the dressing; pass remaining.