For Picadillo:

1. Cook Potatoes: In a skillet, heat the extra virgin olive oil over medium heat. Add the cubed potatoes and cook until they are browned and cooked through. Once done, remove them from the pan and set aside.
2. Brown the Beef: In the same skillet, add the ground beef, minced garlic, and chopped onions. Cook until the beef is browned. As it cooks, season with kosher salt, garlic salt, cumin, oregano, chili powder, paprika, and pepper to taste, ensuring the spices are well distributed throughout the beef.
3. Add Vegetables and Simmer: Add the diced tomatoes and chopped Serrano chiles to the skillet. Let the mixture cook until it thickens a bit. Then, reintroduce the potatoes (and green beans if using) to the skillet. Stir well to combine and let everything simmer together for about 5 minutes.

For Flour Tortillas:

1. Mix Dry Ingredients: In a large bowl, combine the all-purpose flour, salt, and baking powder. Mix these dry ingredients well.
2. Incorporate Shortening: Add the vegetable shortening to the bowl. Use your hands or a pastry cutter to work the shortening into the flour mixture until it resembles coarse crumbs.
3. Form the Dough: Gradually add warm water to the mixture, stirring until a dough forms. The dough should be soft but not sticky. Adjust with a little more flour or water as needed to achieve the right consistency.
4. Rest the Dough: Transfer the dough to a Ziploc bag or cover it with a damp cloth. Let it rest for at least 1 hour. This resting period helps the gluten relax, making the dough easier to roll out.
5. Shape and Cook Tortillas: After the dough has rested, divide it into small balls. On a lightly floured surface, roll out each ball into a thin circle. Heat a griddle or skillet over medium-high heat. Cook each tortilla until bubbles form on the surface, then flip and cook the other side until lightly browned. Keep the cooked tortillas wrapped in a cloth to stay warm.