01 - Combine tuna cubes with soy sauce, sesame oil, lime juice, and chili flakes in a bowl. Let marinate while preparing remaining toppings.
02 - Whisk together sour cream, lime juice, and chopped pickled jalapeños until smooth. Season with salt and pepper to taste. Set aside for serving.
03 - Preheat skillet over medium-high heat. Sear marinated tuna for 30-60 seconds per side, leaving center rare. Alternatively, skip searing for poke-style preparation.
04 - Arrange tortilla chips on serving platter or ovenproof tray. Sprinkle cheese evenly over chips and broil for 1-2 minutes until melted, if desired.
05 - Layer seared tuna over chips, followed by avocado, tomatoes, red onion, jalapeño slices, and fresh cilantro. Drizzle generously with jalapeño-lime crema.
06 - Serve while chips remain crisp and toppings are at peak freshness. Offer extra crema on the side for additional drizzling.