Chicago’s lone Costa Rican eatery turns out burritos bursting with chicken, black beans and fresh avocado, and sandwiches dressed in a heavenly, spicy-sweet vegetable sauce. Wash them down with an avena (a slurpable milkshake in tropical-fruit flavors). For breakfast, the arroz con huevos (peppery eggs scrambled into rice) relieves hangovers. Irazu is BYOB with no corkage fee. Cash only.