Preheat the oven to 400°F. Line a 20 × 14-inch baking sheet or two 14 × 10-inch pans with foil and grease well.
Arrange the kielbasa in a single layer on the baking sheet. Roast for 12 to 15 minutes, until it starts to brown on the bottom.
Meanwhile, in a large bowl, toss together the veggies.
In a small bowl, whisk together the oil, sea salt, Italian seasoning, paprika, garlic powder, and black pepper. Pour over the veggies and toss to coat.
When the kielbasa is done, remove the pan from the oven but leave it on. Flip the kielbasa pieces over and move them to one side of the pan, leaving space for the veggies.
Arrange the veggies in a single layer on the other side of the extra-large pan, or on the second pan if using two pans.
Roast for 18 to 20 minutes, until the veggies are tender and the kielbasa is further browned.