Preheat oven to 375°F.
Spray a cookie sheet with nonstick spray and place tart shells on sheet.
To make the filling: combine the mangos, 1/4 cup sugar, lemon juice and salt in a large bowl; spoon into the tart shells.
To make the topping: combine the flour, coconut, cinnamon and the remaining 1/4 cup sugar in a large bowl.
Add butter, squeezing mixture together to form a loose ball, then break into small pieces and sprinkle evenly over each tart.
Bake until filling is bubbly and topping is golden, about 10 to 12 minutes.
Serving Tips: Serve with whipped cream and diced mango.