Heat gas or charcoal grill. Remove pie crust from pouch; gently press crust in bottom and up side of 8-inch cast-iron skillet, leaving crust overhanging edge of skillet.
Spread grapes in crust. Sprinkle with granulated sugar and salt; drizzle with wine. Gently stir to mix and coat grapes. Sprinkle with almonds.
Fold crust over filling to form 1 1/2-inch rim around top, leaving filling uncovered in center. Brush crust with egg; sprinkle with sanding sugar.
Place skillet on grill over medium-high heat. Cover grill; cook 20 to 25 minutes or until crust is golden brown and grapes are softened.