Cook the eggs in a pot of simmering water for about 9 minutes to make hard-boiled eggs. Run them under cold water to stop the cooking process, then peel them and cut them into wedges.
Meanwhile, cut the tomatoes into wedges, slice the bell pepper into thin strips, and slice the radishes and olives into rounds. Drain the tuna and anchovy fillets.
Arrange a few mesclun leaves on each plate. Arrange the tomato wedges in an attractive pattern, then add the bell pepper strips. Stir in the flaked tuna and anchovies, then top with the radish slices, hard-boiled egg wedges, and olives.
Prepare the dressing by mixing the mustard, vinegar, and olive oil until smooth. Season lightly with salt and pepper, then pour the dressing over the salad.
