Make the dough: stir the sazón and salt into the masarepa, then add the water and oil and mix to a dough. Knead into a ball for 2 minutes until smooth. Cover with plastic and set aside 20 minutes while you make the filling. That rest hydrates the flour so the dough rolls thin without cracking.
Cook the diced potatoes in water with the bouillon tablet for 20 - 25 minutes, until tender. Drain and mash lightly.
Heat the olive oil in a skillet. Cook the onion over medium-low heat 5 minutes, then add the tomato, green onions, garlic, bell pepper, cilantro, salt, and pepper and cook about 15 minutes.
Add the ground pork and beef and cook 10 to 15 minutes, breaking up the meat, until fairly dry. Combine with the mashed potatoes.
Roll ~1 ½ tbsp portions of dough into balls, flatten each very thin between two sheets of plastic, place 1 tbsp filling in the center, fold into a half-circle using the plastic, and crimp the edges shut with a fork.
Heat vegetable oil in a pot to 360°F (182°C). Fry 3 or 4 at a time for about 2 minutes, until golden on all sides. Drain on paper towels and serve with ají and lime.