"My family absolutely love this easy-to-make sausage sandwich. My friends make special dates to come over for a 'Murica Dog Party' several times throughout the summer, when I make them in the great outdoors."
Put sausages into a skillet and pour enough water into the skillet so the sausages are 2/3 covered. Bring water to a boil, place a cover on the skillet, and cook sausages, turning every few minutes, until no longer pink in the center, 8 to 10 minutes. An instant-read thermometer inserted into the center should read 160 degrees F (70 degrees C).
Pour enough oil into a separate skillet to just cover the bottom; heat over medium-high heat. Saute jalapeno pepper in hot oil until softened, 3 to 4 minutes.
Melt 2 tablespoons butter in the skillet with the jalapeno pepper. Once butter is hot, cook onion in hot butter until softened, 4 to 5 minutes. Reduce heat to medium-low, add the kimchi, and cook until soft, 1 to 2 minutes.
Put skillet with sausages over medium heat. Pour onion mixture into the skillet with the sausages.
Return now-empty skillet to medium heat. Melt enough butter in the skillet to cover bottom completely. Grill hoagie buns in batches, adding butter between batches as needed, in skillet until toasted, 2 to 3 minutes per side.
Put a sausage into each toasted bun. Spoon vegetable mixture over each sausage.