Tunisian vegetable stew and Szechwan tofu stir-fry. Certified organic salad bars. Made-to-order panini sandwiches. Bento boxes. Mediterranean tapas and Asian small plates. The restaurant offerings of a good-size city? Not exactly. This is Cal Dining, the foodservice arm of the University of California, Berkeley, where the new Café 3 dining hall offers all-you-can-eat sushi, build-your-own pho and Asian noodle soups, dim sum and such daily specials as pad Thai noodles, Korean beef stir-fry and chicken satay with spicy peanut sauce.