Question: Do you think Vietnam is a little China culturally?
Answer: From the Vietnamese views, there are many Vietnamese will think that you are insulting them if you said Vietnam is a little China culturally.
Vietnam and China shared a lot of cultural similarities due to the common borders and also thousand of years of Vietnam being colonized brutally by China. There are more than once that the Chinese Empire had tried to erase all of the Vietnamese histories, culture, and identity, also imposed the Chinese language, costumes, customs, into Vietnam but the Vietnamese resisted strongly and resiliently. For example: During the fourth Chinese Ming occupation of Vietnam 1407–1428, the Chinese rulers had tried to destroy all of the Vietnamese cultures .
(Khai Dinh king's tomb, Hue - Royal Capital of Vietnam)
An entry in the Ming Shilu ( traditional Chinese : 明實錄; simplified Chinese : 明实录) dated 15 August 1406 recorded an imperial order from Emperor Yongle that instructed for Vietnamese records such as maps and registers to be saved and preserved by the Chinese army:
In addition, according to Yueqiaoshu (Chinese: 越嶠書, Vietnamese: Việt kiệu thư), on August 21, 1406, the Yongle Emperor issued an order to Ming soldiers in Annam:
兵入。除釋道經板經文不燬。外一切書板文字以至俚俗童蒙所習。如上大人丘乙已之類。片紙隻字悉皆燬之。其境內中國 所立碑刻則存之。但是安南所立者悉壞之。一字不存。  "Once our army enters Annam, except Buddhist and Taoist text; all books and notes, including folklore and children book, should be burnt. The stelae erected by China should be protected carefully, while those erected by Annam, should be completely annihilated. Do not spare even one character."
On the 21st day of the 5th lunar month of the following year, Emperor Yongle issued another order to Ming soldiers in Annam:
屢嘗諭爾凡安南所有一切書板文字。以至俚俗童蒙所習。如上大人丘乙已之類。片紙隻字及彼處自立碑刻。見者即便毀壞勿存 。今聞軍中所得文字不即令軍人焚毀。必檢視然後焚之。且軍人多不識字。若一一令其如此。必致傳遞遺失者多。爾今宜一如前敕。號令軍中但遇彼處所有一應文字即便焚毀。毋得存留。  "I have repeatedly told you all to burnt all Annamese books, including folklore and children books and the local stelae should be destroyed immediately upon sight. Recently I heard our soldiers hesitated and read those books before burning them. Most soldiers do not know how to read, so it will be a waste of our time. Now you have to strictly obey my previous command, and burn all local books upon sight without hesitation.
The Chinese colonists encouraging the Ming Confucian ideology, bureaucratic and Classical Chinese study to the local Vietnamese people, forced the Vietnamese to wear Chinese-style clothes .   The Ming forbid the local customs such as tattooing , unmarried boys and girls to cut short hair, and banned women to wear short skirts, in "order to change customs in conformity with the north."   Cultural incorporation was pursued with the new Jiaozhi administration advising to the Ming court:
The Yi people of Annam venerate the law of the Buddha but do not know to worship or sacrifice the spirits. We should establish altars for sacrifice to the spirits of the wind, clouds, thunder, and rain... so that the people become familiar with the way to express gratitude to the spirits through sacrifice. 
(Vietnamese royal palace)
(the Bejing Royal Palace of China built by the Vietnamese architect- Nguyen An)
However, each time, the Vietnamese have tried not only to restore their own culture and identity but also to learn new things from their Chinese cultures which have consolidated the Vietnamese identity different much from the Chinese identity.
For instance: The Vietnamese language belongs to the Austro-Asiatic language but the Chinese language is one of the members of the Sino-Tibetan language family even though the Chinese empires had tried to impose their language into Vietnam and the Vietnamese language has many loanwords from China Especially after the Vietnamese have adopted and learned the western civilization, the Vietnamese culture is more and more different from the Chinese culture.
Another example: During the Chinese Qing Empire, all of the Chinese men had used the Manchu hairstyle as their national identity but Vietnam did not.
(The custom of foot-binding in China but it did not happen in Vietnam)
Vietnam has its habit to defeat superpowers from the Mongolian, Various Chinese Empires, Manchurian Qing Empire, French Empire, American Empire, the Chinese CCP Empire but China often failed to resist outside powers from Mongolia, Manchuria, Japan.
In conclusion : The Vietnamese identity is not a little Chinese identity culturally and there are many differences between Vietnam and China. Therefore, I would not say that Vietnam is a little China culturally.