Heat oven: To 350°F

Make crust:
Combine crushed graham crackers, sugar and salt in processor and process till medium fine . Add butter and process until crumbs are evenly coated. Press crumbs into the bottom and up the sides of a standard 9-inch pie dish. Bake crust until lightly browned, about 10 minutes. Set on cooling rack while you prepare filling. Leave oven on.

Make filling:
Zest limes in a bowl. Beat zest and egg yolks in processor until pale and thick, about 3 minutes. Add sweetened condensed milk and process until thickened again, about 2 minutes more. Squeeze zested limes until you have 2/3 cups juice. Process into yolk mixture until combined. Pour into graham crust and bake pie for another 10 minutes, until set but not browned on top at all. Let pie cool completely before serving