Rub the sugar and cornstarch together in a large bowl, then add the rhubarb and toss until evenly coated.
Spoon the rhubarb mixture into the prebaked pie crust.
Bake in the middle of the oven for 15 minutes, then remove the pie from the oven and turn the oven down to 350°.
Meanwhile, make the custard-using a handheld mixer with beaters or a stand mixer with the paddle attachment, beat the cream cheese and sugar on medium speed until light and fluffy.
Add the eggs one at a time, beating until smooth after each addition and scraping down the sides of the bowl occasionally.
Stir in the vanilla and salt.
Pour the custard into the pie and spread it evenly and smoothly over the rhubarb.
Return the pie to the oven and bake for 25-30 minutes, or until the custard puffs up around the edges but is still slightly wobbly in the middle (do not worry; as the pie cools, the center will firm up.
Cool to room temperature on a wire rack.
Place the strawberries atop the pie and dust with powdered sugar just before serving (a sieve works well for this), or serve the berries alongside with individual slices of pie.
The pie can be made a day in advance, in which case you should refrigerate it and top with the strawberries just before serving.
Covered with plastic wrap, the leftovers will keep in the refrigerator for 2-3 days.