Pastry: Whisk flour with salt until combined; cut in butter with a pastry blender or your fingertips until mixture resemble coarse meal. Stir 2 tbsp (30 mL) water into the flour mixture until dough comes together, adding 1 tbsp (15 mL) more water if needed.
Shape into ball and flatten into disk; wrap with plastic wrap and refrigerate for at least 1 hour or up to 2 days.
Preheat oven to 400°F (200°C). On lightly floured work surface, roll pastry into 12- x 8-inch (30 x 20 cm) rectangle, about 1/4-inch thick. Fit into 11- x 7-inch (28 x 18 cm) rectangular tart pan with removable bottom; trimming away excess dough.
Prick bottom of pastry with a fork. Line with foil or parchment paper; fill with pie weights. Bake in bottom third of oven for 20 minutes. Remove foil and weights; bake until golden brown, approximately 7 to 10 minutes. Let cool completely.
Filling: Preheat oven to 350°F (180°C). Whisk together eggs, cream, salt, pepper and smoked paprika; set aside. Mix together potato, chorizo, red pepper, green onions, parsley and garlic; scatter over tart crust. Sprinkle with cheese. Pour egg mixture over top. Bake in centre of oven until filling is set but still jiggles slightly in the centre, approximately 30 to 35 minutes. Let stand for 15 minutes before slicing; serve warm or at room temperature.