Heat a skillet over medium heat and add vegetable oil, letting it shimmer.
Add the chopped onion to the skillet and cook, stirring occasionally, until it softens and becomes translucent, about 3-4 minutes.
Add the minced garlic and cook for another 30 seconds until fragrant, stirring constantly to prevent burning.
Increase the heat to medium-high and add the ground beef to the skillet, breaking it apart with a spatula or wooden spoon.
Cook the beef, stirring frequently, until it browns evenly and is cooked through, about 8-10 minutes.
Season generously with salt and pepper, and stir to incorporate the seasonings evenly.
Reduce the heat to low, and let the mixture simmer for a couple of minutes to meld the flavors.
While the beef simmers, lightly toast the hamburger buns until golden on the cut sides.
Spread a generous portion of the seasoned beef onto the bottom half of each toasted bun.
Top with desired toppings like pickles, ketchup, or onions, then place the top bun over the meat.
Serve the loose meat sandwiches hot, with plenty of napkins for easy eating.