Crab and Cream Cheese Pizza

Name: Crab and Cream Cheese Pizza
Ingredients: 1 pound jumbo lump crabmeat; 8 ounces cream cheese, at room temperature; 1/2 cup drained and chopped water chestnuts; 1/4 cup mayonnaise; 1 tablespoon low-sodium soy sauce; 2 teaspoons Chinese hot mustard, plus more for serving; 1 teaspoon toasted sesame oil; 2 scallions, sliced, plus more for garnish; 1 clove garlic, finely chopped; Kosher salt and freshly ground white or black pepper; All-purpose flour, for dusting; 1 pound store-bought pizza dough, at room temperature; 1 large egg; 2 teaspoons white sesame seeds or black sesame seeds (or a combination); Duck sauce, for drizzling; Chow mein noodles, for garnish