How to Make It
Preheat the oven to 350° and arrange six 4 1/2-inch fluted tart pans on a baking sheet. In a food processor, pulse the graham crackers until very finely ground (you should have about 2 cups). Add the oil, agave and salt and pulse just until the mixture starts to come together. Press the crumbs evenly over the bottom and up the sides of the tart pans (use about 1/3 cup of the crumbs per pan).
Bake the shells for about 10 minutes, until just firm. Let the shells cool completely, then carefully remove them from the pans.
In a medium saucepan, combine the pear juice with the lemon juice, arrowroot and agar. Cook the mixture over moderate heat, whisking constantly, until slightly thickened, 5 to 7 minutes. Strain the mixture through a fine sieve into a heatproof bowl and let cool completely.
In a food processor, combine the tofu with the agave, vanilla and lemon zest and puree until smooth. Add the cooled pear mixture and puree just until incorporated. Pour the mixture into the prepared shells, cover and refrigerate until set, about 8 hours or overnight. To serve, top the tarts with quartered strawberries and crushed pistachios.
Agar powder is a colorless type of gelatin made from seaweed that sets without chilling. It is available at some health food shops, Asian markets and from amazon.com.