Pour enough water into a large skillet to barely cover the bottom. Add the bacon, set over medium-high heat, and cook until the water is evaporated and the bacon is starting to sizzle. Reduce the heat to medium and cook, stirring often, until the bacon is lightly browned, about 5 minutes. Scrape onto a paper-towel-lined plate to drain.
Pour the bacon fat from the pan and wipe out the pan. Add the olive oil and garlic, return the pan to medium heat, and cook until the garlic is fragrant, a minute or two. Add the shrimp and stir until they turn pink, then stir in the tomato and continue cooking until the shrimp are cooked through, about 2 minutes. Season with salt and pepper to taste. Remove from the heat and stir in the scallions, crushed red pepper, and bacon. Let cool completely.
Using a scant 1/3 cup filling for each, form and cook the empanadas according to the directions below.
To form the empanadas:
Moisten the edges of each empanada wrapper with a fingertip dipped in warm water, and center a generous 1/3 cup of the filling on the wrapper. Bring the sides of the wrapper together to meet over the filling to form a half-moon shape, and press the edges together to seal.
To crimp the edges:
Lay the empanada flat on the work surface. Work your way around the edges of the half-moon, folding the edges to make 1/2-inch pleats. Press as you go to seal the pleats. Or, if you don't want to mess with crimping, just press down on the edges with the tines of a fork.
To fry the empanadas:
Pour enough vegetable or canola oil into a large heavy skillet to come to about 3/4 inch. Heat over medium heat until the tip of the handle of a wooden spoon immersed in the oil gives off a lively sizzle (about 360°F). Carefully slip only as many empanadas at a time into the oil as will fit without crowding. Cook until the dough is lightly browned, about 3 minutes. Carefully flip and repeat. Drain briefly on paper towels before serving.
To bake empanadas:
Preheat the oven to 375°F. Line a baking sheet with parchment paper (or use a nonstick baking sheet). Brush the empanadas lightly with beaten egg and bake until they are light golden brown, about 25 minutes. Cool for a few minutes before serving.
Empanada wrappers, either plain or seasoned and/or colored, are available frozen (sometimes refrigerated) in many supermarkets and almost all Latin markets. Goya is the most common brand. A 10-ounce package of 6-inch empanada wrappers usually contains 10 wrappers. For best results, defrost the wrappers overnight in the refrigerator.