1. Make curd: In a pan, whisk yolks, zest, juice, sugar and salt. Cook over medium heat, whisking constantly, until mixture thickens, 8 to 10 minutes.
2. Remove from heat; whisk in butter, one piece at a time, until melted. Strain into a bowl. Cover with plastic wrap, pressing directly onto surface of curd. Refrigerate at least 4 hours.
3. Make crust: Stir coconut, crumbs and butter until blended. Firmly press onto bottom and up sides of a 10-inch tart pan. Chill 30 minutes.
4. Preheat oven to 350ºF. Bake crust until golden, 15 to 20 minutes. Let cool on a rack.
5. Spread curd in crust. Remove tart from pan; slice and serve.