1. Heat oil in a cast iron or wok until around 325-350 degrees.
2. Place the minced shrimp in a mixing bowl. Add egg white, soy, sesame oil, ginger, garlic, scallion, cilantro, cornstarch, and hot mustard to bowl and mix thoroughly. Season with salt. (Alternatively add all of these ingredients to a food processor and pulse until finely minced and incorporated.)
3. Spread the mixture over one half of the potato bread triangles.
4. Place the toast, shrimp side down into the heated oil and fry for a minute-and-a-half or two, or until golden brown. Flip toast and fry bottom half for another minute or so. Transfer to a paper-towel-lined plate.
5. Garnish with scallion, sesame seed and a drizzle of hot mustard. Serve warm.