Separate the egg yolk from the white. Thinly slice the white. Put the egg yolk in a blender, add the vinegar and honey and blend until smooth. With the blender on, slowly pour in the 2 tablespoons plus 2 teaspoons of oil. Season the dressing with salt and pepper.
In a medium skillet, heat 1/4 inch of oil. Add the shallot rings and fry over moderate heat, stirring a few times, until golden brown and crisp, about 3 minutes. With a slotted spoon, transfer the shallot rings to paper towels to drain. Add the garlic to the hot oil and fry, stirring a few times, until golden, about 1 minute. Transfer the garlic to the paper towels.
In a large bowl, drizzle the tomato and cucumber slices with 1 tablespoon of the dressing and toss gently. Arrange the slices around a platter. Add the mesclun, watercress and sliced egg white to the bowl, top with the remaining dressing and toss well. Mound the salad on the platter, garnish with the peanuts and the fried shallot and garlic and serve.
MAKE AHEAD The dressing can be refrigerated overnight. The fried shallot and garlic can be kept overnight at room temperature.