Preheat the oven to 400 degrees F.
In a bowl, combine 1/2 cup whole milk and 1 teaspoon lime juice. Cut 2 slices white sandwich bread into 1-inch cubes and soak the cubes in the milk mixture for 10 minutes.
Mash the soaked bread cubes with a fork until mostly broken down.
In a large bowl, stir together 1 pound ground beef and the mashed bread mixture.
Mix in 1/3 cup finely chopped cilantro, 4 teaspoons soy sauce, 2 garlic cloves (peeled and minced or pressed), 2 teaspoons finely grated fresh ginger root, and 1 large egg until evenly combined.
Form 18 to 20 meatballs (about 2 tablespoons per meatball) using a spring-loaded metal scoop or a large spoon and place them directly on non-stick baking sheets; there is no need to grease or line the sheets.
Bake the meatballs until cooked through and brown on the outside, about 20 minutes.
To make the hot chili oil, heat 2 tablespoons vegetable oil with 1/2 teaspoon crushed red pepper flakes in a pan until the oil is sizzling, then let the oil cool.
Drizzle a few drops of the hot chili oil onto the meatballs or serve the oil as a dipping sauce.