In offices it would usually be from ~14h to 15h or 15:30h. Open to the public, street-level, small businesses (let's say, a butcher, a small hardware store, a bakery...) usually close from 14h to 16h or 16:30h. They open till later than other countries, though, often till 20h or so. That can vary per region and the size of the city, of course.
But not for siesta, for lunch. And, by lunch, for HNers, I mean a mid sized meal, not just a sandwitch.
The problem is Spain is that we have the breakfast and lunch kinda the opposite as the Brits.
Brits eat a big breakfast and a small lunch. We do the opposite. Some coffee and maybe a small pastry, and we are done for breakfast. For luch, we have a first and second dish and a dessert.
