Preheat the oven to 350° F (180° C.) Line 12 muffin cups with papers. In a medium bowl, add the flour, salt, baking powder, and baking soda, and stir until they are well combined. In a separate bowl, juice and zest the oranges. Pour the juice from the can of pineapple into the orange juice.
In a large mixing bowl, add the oil, sugar, vanilla extract, orange juice, orange zest, pineapple juice, and eggs. Whisk these wet ingredients until they are well combined. Next, add the flour mixture one cup at a time, whisking it into the batter until it is just combined. Finally, use a spoon or spatula to fold in the crushed pineapple.
Divide the batter evenly into the 12 muffin cups and bake at 350° F (180° C) for about 20-23 minutes, or until the tops are springy to the touch. Allow the cupcakes to cool for about 45 minutes before frosting.