In a medium bowl, stir together the eggs, mayonnaise, mustard, salt and pepper to combine.
Place one sheet of the nori, shiny side down, onto a clean surface. Dollop about ¼ cup of the egg salad in the center of the nori toward the top of the sheet, then place a quarter of each of the cucumber, scallion and microgreens on top. Fold the bottom of the nori over the egg salad, then roll up into a wrap. Repeat with the remaining ingredients and serve.
