Preheat oven to 325°F (160°C).
Mix graham cracker crumbs, melted butter, sugar, and salt in a bowl until combined.
Press the mixture firmly into the bottom of a 9-inch springform pan. Bake for 10 minutes, then let it cool.
In a mixing bowl, beat cream cheese until smooth.
Add sugar and mix on low speed until fluffy.
Blend in sour cream, cream of coconut, cornstarch, and coconut extract.
Add eggs one at a time, mixing on low speed after each addition.
Fold in crushed pineapple, pineapple juice, and rum (if using).
Wrap the outside of the springform pan with heavy-duty foil if using a water bath.
Pour the batter over the cooled crust and smooth the top.
Bake for 60-75 minutes until the edges are firm but the center still jiggles slightly.
Turn off the oven, crack the door open, and let the cheesecake sit for 20 minutes before removing.
Cool completely at room temperature, then refrigerate for at least 4 hours or overnight.
Garnish with whipped cream, toasted coconut flakes, maraschino cherries, and pineapple chunks before serving.