Make the compote: Preheat the oven (with one of the racks positioned in the center) to 375° F. To a large bowl, combine the rhubarb and strawberries with ¾ cup sugar, the orange zest and juice, and the potato starch and salt, and toss to combine. Spread the mixture out in a single layer on a large rimmed baking sheet, transfer to the oven, and roast until the fruit is tender but is still holding its shape, 15–18 minutes. Remove the rhubarb and strawberries from the oven and use a slotted spatula to transfer the roasted fruit to a wide bowl to cool to room temperature. Meanwhile, pour any accumulated strawberry-rhubarb juices into a small pot, bring to a simmer over medium heat, and cook until thickened and syrupy, 2–3 minutes. Remove from heat and set aside to cool to room temperature, stirring occasionally. When cool, pour the syrup over the roasted fruit, cover, and refrigerate.
Prepare the cream: In the bowl of a stand mixer fitted with a whisk attachment, whip the mascarpone, vanilla bean seeds, cream, and the remaining 2 tablespoons of sugar on medium speed to medium-stiff peaks, about 1 minute. (Take care not to overwhip the mixture which causes it to turn grainy.) Cover and transfer to the fridge.
Prepare the crust: Lower the oven to 325° F.. Line a large rimmed baking sheet with parchment paper and set aside.
In a large bowl, whisk together the oil, honey, maple syrup, orange juice, cinnamon, cardamom, salt, and vanilla bean seeds. Add the matzo and stir to coat thoroughly. Set aside for ten minutes, tossing occasionally. Spread the matzo mixture and any accumulated liquid onto the baking sheet, transfer to the oven, and bake until toasty and fragrant, about 15 minutes. Add the chopped pistachios, and the unsweetened and sweetened coconut, stir to combine, and continue baking, stirring occasionally, until the mixture is golden and dry, about 10 minutes more. Remove from the oven and set aside to cool to room temperature.
When the matzo mixture has cooled, transfer half of it to the bowl of a food processor fitted with the blade attachment and pulse to process to medium-fine crumbs. Transfer to a medium bowl and repeat with the second half of the matzo mixture. Add the melted butter to the crumbs and toss to combine. Sprinkle the crumb mixture across the bottom and up the sides of a greased 9½- by 1¼-inch fluted tart pan with a removable bottom. Using the flat bottom of a measuring cup, press the crumbs in an even layer across the bottom and up the sides of the pan. Refrigerate the tart shell until firm, about 15 minutes.
Place the tart shell in the center of the baking sheet. Transfer to the oven and bake until firm and very fragrant, about 10 minutes. Remove from the oven and immediately use the bottom of the measuring cup to again press and pack the crumbs against the fluted sides of the pan, reinforcing the outer crust. Set aside to cool to room temperature.
Assemble the tart: Pour the mascarpone cream into the cooled tart shell, then use an offset spatula or the back of a spoon to spread in an even layer. Spoon the compote evenly over the cream. Transfer to the fridge for at least an hour or overnight.
To serve, carefully remove the outer ring from the tart shell and slide the tart onto a large, flat serving plate. Use a sharp knife to cut into slices and serve chilled. Cover and refrigerate any leftovers for up to 3 days.