Tear the tortillas into small pieces and place in a food processor. Add the milk, egg, salt, and pepper. Process until a chunky paste forms and you are able to squeeze a ball together in your hand, stopping to scrape down the sides of the bowl as needed. Transfer to a mixing bowl and stir in the onions and jalapenos. Set aside.
Place the oil in a 5-quart Dutch oven fitted with a deep-fry thermometer set over medium heat and heat to 365 to 375ºF.
Roll the dough into 1- to 1 1/2-inch balls, or scoop with a 2-teaspoon ice cream scoop. Fry 6 to 8 at a time in the oil until crisp and golden brown, 2 to 3 minutes. Transfer to a wire rack set over a paper towel-lined half-sheet pan and allow to cool 2 minutes before serving.