Gluten free shopping in Le Petit Senegal? Mais, bien sur! Along West 116th Street, from 7th to 8th Avenues, give or take a block, you will find many gluten-free treasures, but they won't be the kind you usually see on gluten-free online shopping sites or at Whole Foods or other health stores, for that matter. Though most shop owners seem to speak at least some English, any French you have will be useful.
Famous along the street is the African Market, with its wide selection of clothing, sculpture and craft items. The cloth pictured below is African, bought in Manhattan, though not from this particular market. But perhaps your time would be best spent in the food shops, which carry products that are almost never found beyond ethnic neighborhoods like this one. Above is millet couscous, millet flour made into small balls approximately the size of Israeli couscous, but gluten free, which the Israeli version is not. Pictured below is couscous made of rice. See the slideshow for more products, including plantain flour, millet flour and yam-coconut flour.