How to Make It
In a small bowl, whisk the sugar with 1/2 cup of warm water until dissolved. Whisk in all of the remaining ingredients.
In a food processor, combine all of the ingredients except the baguette slices, canola oil and garnishes and puree until nearly smooth. Spread the mousse on the baguette slices.
In a large nonstick skillet, heat 3 tablespoons of the oil. Add half of the toasts, mousse side down, and cook over moderate heat until golden, 2 minutes. Flip the toasts and cook until browned on the bottom, 1 minute. Transfer the toasts to paper towels to drain. Repeat with the remaining oil and shrimp toasts. Transfer the toasts to a platter, garnish with cilantro and scallions and serve with the nuoc cham.