Place racks in upper and lower thirds of oven and preheat to 425°F. Line two baking sheets with parchment.
In a large bowl, toss vegetables with 2 Tbsp. oil, 1 tsp. each cumin, salt and pepper until evenly coated. Transfer to baking sheets. Roast, rotating pans and tossing once halfway through cooking, until vegetables are tender and golden brown in spots, 40 to 45 minutes.
In a small bowl combine 1/4 tsp. cumin, smoked paprika, sugar and 1/4 tsp. each salt and pepper.
Warm 1 tsp. oil in a medium skillet over medium heat. Add pumpkin seeds and toss to coat. Cook, stirring constantly, until evenly toasted, 3 to 4 minutes. Add spice mixture to skillet and toss until coated and spices are toasted, about 30 seconds. Transfer pumpkin seeds to a flat plate to cool.
Transfer vegetables to a platter and sprinkle with pumpkin seeds. Serve warm or at room temperature.