1. Peel Jerusalem artichokes and rinse.
2. In a 5- to 6-quart pan over high heat, bring 2 quarts water to a boil. Add Jerusalem artichokes and cook until tender when pierced, about 12 minutes. Drain.
3. In a blender or food processor, whirl Jerusalem artichokes, garlic, lemon juice, and oil until smoothly puréed; scrape container sides as needed. Add chilies and salt to taste. Scrape into a bowl.
4. To eat, scoop up dip with corn chips.