Heat oven to 350°F. Stir crumbs, melted butter, and salt until evenly moistened.
Press mixture firmly into a 9-inch pie plate, covering bottom and sides. Bake 8–10 minutes, then cool completely.
Warm dulce de leche briefly until spreadable. Whisk in espresso powder if using, then spread over the cooled crust.
Toss banana slices with lemon juice. Arrange in an even layer over the caramel.
Whip cold cream, powdered sugar, and vanilla to soft peaks.
Spread the whipped cream over bananas, sealing to the crust edges.
Chill 30–40 minutes for cleaner slices. Top with chocolate shavings, slice, and serve.