This is a way to eat oranges that is typical from Jaen, one of the best known olive oil producing areas in Spain. All you need to do is to slice an orange, sprinkle sugar on top and then drizzle some (good) olive oil. It is an unusual taste but it works well. The children liked it though they prefer the oranges with just sugar on top or on their own.
If you like the taste of olive oil you can also toast some bread, drizzle it with olive oil and sprinkle sugar on top. This (with a strong coffee) is the breakfast of many people in the South of Spain.