Place the cherries in a medium sauce pan with a lid.
Combine the sugar, corn starch, cinnamon and salt. Sprinkle over the cherries. Pour the amaretto over the cherries, and stir to fully coat the cherries.
Cover and set to a medium heat until it comes to a boil. Reduce to a simmer for half an hour, stirring every five minutes.
Remove to an air tight container and store in the refrigerator over night or up to a week before you build your pie. If you feel like you might want to save this for longer, I recommend getting a quart-sized mason jar, and doing a proper canning of it.