Preheat oven to 400°F.
To make the graham cracker crust, mix together the graham crackers, coconut oil, and 1/4 cup sugar in a bowl. Press crust into the bottom of a 9-inch spring form pan. Bake until lightly browned (about eight minutes) and cool.
Once the crust has been baked, lower the oven temperature to 350°F.
To make the cheesecake, blend cashews in a food processor until they form into a paste. Add tofu, coconut milk, 1/2 cup sugar, lemon juice, cornstarch, and vanilla extract into the processor and blend until smooth.
Pour cheesecake mixture over the cooled crust. Bake for 40 minutes and then cool.
To make the mango-lime topping, add mangos, 1/4 cup sugar, lime juice, lime zest, and water into a pan over medium heat. Once mixture begins to simmer, lower the heat and stir occasionally until the ingredients are the consistency of syrup (about 20 minutes). Cool topping.
Pour cooled topping on top of cooled cheesecake and spread evenly. Refrigerate for an hour or more and then serve.