Cheesy Nachos with Guacamole and Salsa

FOR ONE-MINUTE SALSA: Pulse all ingredients except tomatoes in food processor until minced, about five 1-second pulses, scraping sides of bowl as necessary. Add tomatoes and pulse until roughly chopped, about two 1-second pulses. The salsa can be refrigerated, wrapped tightly in plastic wrap, for up to 2 days. Season with additional lime juice and salt to taste before serving.

FOR FRESH GUACAMOLE: Halve 1 avocado, remove pit, and scoop flesh into medium bowl. Using fork, mash lightly with onion, garlic, jalapeno, cilantro, and 1/8 teaspoon salt until just combined.

Halve and pit remaining avocado. Using a dinner knife, carefully make 1/2-inch cross-hatch incisions in flesh, cutting down to but not through skin. Using a soupspoon, gently scoop flesh from skin; transfer to bowl with mashed avocado mixture (see illustrations below). Sprinkle lime juice over and mix lightly with fork until combined but still chunky. Adjust seasoning with salt, if necessary, and serve. (Can be covered with plastic wrap, pressed directly onto surface of mixture, and refrigerated up to 1 day. Return guacamole to room temperature, removing plastic wrap just before serving.)

FOR NACHOS: Adjust oven rack to middle position and heat oven to 400 degrees. Spread half of chips in even layer in 13- by 9-inch baking dish or similar ovenproof platter; sprinkle evenly with 2 cups cheese and half of jalapeño slices. Repeat with remaining chips, cheese, and jalapeños. Bake until cheese is melted, 7 to 10 minutes. Remove nachos from oven, cool 2 minutes, then sprinkle with scallions. Along edge of nachos, drop scoops of guacamole, sour cream, and salsa. Serve immediately, passing lime wedges separately.