Set a heavy skillet or comal over medium-high heat. Add the roma tomatoes, serrano chiles, the white onion (slice it into thick slabs), and the garlic clove; dry-roast, turning occasionally, until blistered with charred spots and softened, 8–12 minutes.
Transfer the roasted vegetables to a blender; peel the garlic. Add the fresh cilantro, fresh lime juice, and up to 0.25 cup water. Pulse for a coarse salsa or blend until smooth, adding only as much of the measured water as needed to reach a spoonable consistency.
Stir in 1 teaspoon of the kosher salt; reserve the remaining 1 teaspoon for the chips. Adjust acidity to taste and set the salsa aside to cool to room temperature.
Pour the vegetable oil into a medium heavy pot to a depth of about 1 inch. Heat over medium to 350°F (the oil should shimmer and bubble quickly around a wooden spoon handle).
Cut the corn tortillas into 6 wedges each and separate the pieces so they don’t stick.
Working in batches, slide a handful of tortilla wedges into the hot oil and fry, stirring and turning, until bubbled, crisp, and just lightly golden, 2–3 minutes per batch.
Lift the chips to a rack or paper towels to drain, then immediately sprinkle with the reserved salt while still hot.
Repeat with the remaining tortilla wedges, keeping finished chips in a warm, dry spot so they stay crisp.
Transfer the salsa to a bowl and the chips to a basket. Serve right away with lime wedges.