Add the potatoes to a medium skillet on high heat, and spread out evenly. Add enough water to cover potatoes by 1". Bring water to a boil and add the salt. Let the water continue boiling until potatoes are soft, about 10-15 minutes. Periodically use a fork to test them.
Meanwhile, heat another medium-large skillet on medium and add 2T of the cooking oil. Once heated, add onion, peppers, and garlic. Cook for 5-7 minutes, stirring frequently. When done, scoop into a separate bowl and set aside.
Using the same skillet on medium heat, add sausage and cook until no longer pink, breaking it up into smaller pieces as it cooks. Once sausage is cooked, add mushrooms, corn and the veggie mix (from Step 2) to skillet. Season with salt & pepper and cook for 5-7 minutes. Stir frequently.
Once potatoes are soft, remove from water and pat dry with a paper towel. Pour the water out of the skillet. Add the remaining 2 T of the cooking oil to the skillet that held the potatoes and heat on medium. Add potatoes back to the skillet and season them liberally with salt & pepper. Panfry until the the sides of the potatoes are slightly golden brown.