1
Wash and dry produce.
Halve, peel, and thinly slice half the onion; finely chop remaining. Zest and quarter lime. Peel and mince or grate garlic. Trim and discard root end from lettuce; halve lengthwise, then chop crosswise into 1-inch ribbons. Dice tomato into ½-inch pieces. Gently crush tortilla chips in their bag into small pieces.