In a mixing bowl, combine the mustard, vinegar, salt, garlic, peanut oil, olive oil, pepper and thyme. Beat with a fork until well blended and set aside.
Pick over the beans and break them into 1½ Inch lengths. Place in a saucepan and cook in salted water to cover until tender but crisp. Drain and run under cold water, then drain in a colander and set aside.
Remove the cores, seeds and white membranes from the green peppers. Cut the peppers into thin rounds and set aside.
Trim the celery stalks and cut crosswise into thin slices. There should be about 2 cups of sliced celery. Set aside.
In a large salad bowl, make a more or less symmetrical pattern of the green beans, peppers, celery, tomatoes and potatoes. Flake the tuna and add to the bowl. Arrange the anchovies on top and scatter the olives over all.
Peel the onions and cut into thin, almost transparent slices. Scatter the onion rings over all. Sprinkle with basil, parsley and scallions. Garnish with hard-cooked eggs if desired.
Toss the salad with dressing after garnished bowl has been presented to the guests for their enjoyment. Serve with a crusty loaf of French or Italian bread.