1. Remove husks from tomatillos; wash thoroughly.
2. Sauté onion in hot olive oil in a large saucepan over medium-high heat 5 minutes or until softened. Add garlic, and sauté 1 minute. Stir in tomatillos, 1 cup water, and jalapeño; bring to a boil. Reduce heat to medium; cover and simmer, stirring occasionally, 10 to 12 minutes or until tomatillos are softened. Remove from heat; cool slightly.
3. Process tomatillo mixture, cilantro, lime juice, and salt in a food processor or blender until smooth. Cover and chill at least 8 hours. Serve at room temperature with tortilla chips.