Preheat the oven to 325 degrees.
In a large mixing bowl, combine the olive oil, 1/2 teaspoon salt, the pumpkin pie spice, maple syrup and pumpkin puree. Whisk to combine. Add the oats, pecans, and sesame seeds. Stir until all of the dry ingredients are evenly coated.
Line a large baking sheet with parchment paper. Spread the granola mixture in an even layer on the baking sheet, leaving some clusters of oats and nuts intact so that the finished granola will be somewhat chunky. Bake the granola, stirring occasionally, until dry and golden brown in color, 35 to 45 minutes.
Remove the pan from the oven and allow the granola to cool for a few minutes. Add the raisins and toss to mix. Add another pinch or two of salt if needed.
Cool the granola completely before storing. It will keep in an airtight container for up to 2 weeks.