Preheat the oven to 375º F.
Place a sheet of parchment over a baking sheet. Roll out the dough sheet onto the parchment; set aside.
.In a mixing bowl, add the pesto, drained sardines, cream cheese, pine nuts, capers, feta, olives, and spinach. Mix the ingredients with a spoon until the sardines are broken down and everything is well combined. (The mixture won't look pretty, but that's okay!)
Spoon the mixture onto the dough sheet and spread it out evenly, leaving about 1/2 inch of space around the edges.
Starting from the shorter end of the pastry, start rolling forward, ensuring that the roll is tight. (This will give you larger pinwheels, but less of them. You could also roll upward from the long side, giving you more pinwheels at a smaller size.)
Once tightly rolled, gently slice the log into 1/2-inch slices, placing them on the parchment about an inch or so apart.
Bake in the oven for 10-13 minutes, or until the pastry is golden brown.When ready, remove the pinwheels from the oven and let them sit for a few minutes to cool. Then serve.