In Cidade Baixa, you will find a square, keep walking and you will get to a souvenir market. The market has two floors, the first with souvenirs, and the second with more souvenir shops and a couple of nice restaurants with bay views.
I do recommend having lunch in either one of the restaurants, both offer similar dishes, seafood and Bahian food. If you want to spend less, by the south gate you will find some open air bars, where you can have something to eat. On the second floor of the market there is also a lunchonete (snack bar) that sells sandwiches.