In a large skillet, heat a tablespoon of neutral oil over medium-high heat. Sauté yellow onion and pickled jalapeños until soft and translucent, about 5 minutes. Stir in minced garlic and tomato paste; cook until the paste darkens, about 2-3 minutes.

Add ground beef to the skillet with the sofrito mixture, sprinkle in taco seasoning and kosher salt. Cook while breaking up the meat until browned and cooked through, about 7-10 minutes. Remove from heat and let cool slightly.

Combine cheddar and pepper jack cheese in a medium bowl. In a small bowl, whisk together flour with fresh lime juice until smooth. Set both aside for assembly.

Warm corn tortillas until pliable, about 30 seconds. On each tortilla, place a spoonful of beef filling followed by a sprinkle of cheese. Roll tightly, brushing the edge with flour paste to seal.

To cook, choose baking or frying. For baking, preheat oven to 400°F, place taquitos seam-side down on a baking sheet and bake for 15-20 minutes. For frying, heat oil in a deep skillet to 375°F and cook for about 5 minutes until golden brown. Drain on paper towels.

In a small bowl, mix sour cream, chopped cilantro, and lime juice for a dipping sauce. Season with salt to taste and chill until ready to serve.