Although I've had lunch/dinner in 4 out of the 7 towns listed I don't remember the name of any particular restaurant. What is good, though, is that in all places, food was very decent (typical "southern" cuisine, olive oil no butter
). The only general suggestions I have is to "plan" a few hours in Matera (actually not in Puglia but in Basilicata) and at least one evening in Lecce (beautiful during the day too, but stunning after dark). As for grocery stores, small ones are closed for lunch/siesta (usually from ~1 till ~4) Mo-Sa and all day on Su, big supermarkets are usually open throughout the day during the week and sometimes on Sunday too, opening between 10 and 11 am. Grocery stores are always open on Monday mornings. "Farmers' markets" are found in several towns/villages, often on only one day of the week (closed in the afternoon) as well as on Saturdays in the major town of a wide area, but there is no way of really knowing unless you ask locally. Buying bread and salami or something "similar" should be fine for lunch and will keep you fit till dinner. Actually, you will not get tired of eating stuff like that
.
Have a nice vacation, Puglia is a lovely place.