I would say that Cisneros does not claim her Chicano culture to be wholly unique and separated from other ethnic cultures in the United States or from the American mainstream. As the narrator of the sketches points out, what she longs for is a dialogue (not assimilation) between cultures as well as between her own ethnicity and the American mainstream. While Esperanza exhibits pride in some ethnic customs and traditions, the narrator seems to find certain aspects of her culture (particularly the patriarchal bias) constraning and oppressing.
Yet, you're right in pointing out how some of the sketches in the collection describe some ethnic rites and ceremonies such as baptism and the ensuing family party ("Chanclas") or focus on the plight of characters such as Mamacita ("No Speak English") who cannot accept the new environment as her home and keeps singing songs about her native country, refusing to learn English. Esperanza is also described as superstitious like her mother and in the sketch "Elenita, Cards, Palm, Water" we follow her to the house of Elenita, a fortune teller. It is significant that while some of Elinita's remedies or prophesies may just sound pure superstition (rub a cold egg against your face to get rid of a headache) or what is expected from a good Chicana (you will marry soon), she suggests a deeper truth when she coins the expression "a home in the heart". For someone like Esperenza, who is dissatisfied with her material home on Mango Street, the expression points to the necessity of building her own spiritual home, thus finding a satisfactory identity that negotiates Chicano and American culture.