Preheat the oven to 350°F (180°C). Line a 10-inch (25-cm) springform pan with parchment paper and grease the sides with nonstick spray.
Bring a small pot of water to a boil. Add the cashews and boil for 10 minutes, until fork-tender. Drain and set aside.
Add the graham crackers to a food processor and pulse until they break down into crumbs. Pour in the coconut oil and pulse until combined. Transfer to a medium bowl and clean out the food processor.
Add the cashews, tofu, pumpkin puree, sugar, cornstarch, pumpkin pie spice, vanilla extract, lemon juice, and salt to the food processor. Puree for 5-8 minutes, or until the mixture is completely smooth and not at all gritty.
Add the graham cracker crumbs to the prepared pan. Use a flat-bottomed measuring cup to help pack the crust in an even layer.
Using a spatula, spread the filling over the crust in an even layer.
Bake for 20-25 minutes, until the cheesecake is set.
Refrigerate uncovered for at least 4 hours, or overnight.
Unmold the cheesecake, then slice and serve with non-dairy whipped cream.