Move an oven rack to the middle and heat the oven to 400°F.
Add the sliced onions, peppers and potatoes to a large baking dish or Pyrex. Pour in the olive oil and stir until the vegetables are coated. Add the salt, garlic salt, paprika, and fresh ground pepper. Stir again until the vegetables are coated with the spices.
Make little beds for the sausage links in the vegetables either with your hands or with a spoon. Place the sausages in the vegetables (see image above). Cover with foil and bake for 40 minutes. Remove the foil and bake on for an additional 10 minutes to let the vegetables crisp.
If you would like the vegetables crispier or they are not fully cooked, remove the sausage links and put the vegetables uncovered back in the oven. Cook for an additional 5-10 minutes.
Eat as is, on a hoagie roll or over pasta. On a hoagie roll or baguette is my favorite :).