Prepare the filling: Bring a small saucepan of water to a boil. Add the noodles and blanch until tender, 1 to 2 minutes, then strain and run under cold water. Roughly chop into small pieces and transfer to a large bowl.

Place the shrimp, scallions, and garlic into the bowl of a food processor and pulse until ground; it should be smooth enough to spread.

Transfer to the bowl with the noodles along with the sugar, fish sauce, salt, and black pepper and mix to combine. Season to taste with the fish sauce.

Spread the shrimp filling evenly over the slices of bread, then refrigerate at least 1 hour, or until ready to fry.

Make the mango sweet chili sauce: Combine the chili sauce and sugar in a blender and purée until smooth, then add the mango and continue to purée until completely smooth. Set aside until ready to use.

Make the piperade: In a small saucepan, combine the palm sugar and ¼ cup|60 ml water and bring to a boil. Reduce the heat to maintain a simmer and cook until reduced and sticky, about 5 minutes.

In a medium skillet, heat the olive oil over high. Add the bell peppers and garlic and cook until just soft, 4 to 5 minutes. Season with salt, then add the palm sugar-water mixture. Stir to combine and set aside until ready to use.

Make the cucumber salad: Slice the cucumbers into 3-inch ribbons on a mandolin, then toss in a large bowl with the red onion and olive oil and season to taste with salt. Set aside until ready to use.

Meanwhile, heat 3-inches of oil in a large Dutch oven until a deep-fry thermometer reads 350°F.

Working in batches, fry the toasts, flipping once, until golden and crisp, 3 to 4 minutes. Use a spider to submerge the toast completely in the oil during frying.

When finished, drain well over a rack or pat down with a paper towel.

To serve, cut the toasts into 4 to 6 pieces and place on a serving platter. Drizzle mango sauce over slices and garnish with the cucumber salad, piperade, and herbs.