In a medium jar, combine the Dijon mustard, Italian seasoning, red wine vinegar, garlic, lemon juice, salt, black pepper, and olive oil. Top with lid and toss to combine.
Place the chopped lettuce into a large bowl. Top with cherry tomatoes, steamed green beans, potatoes, salmon, eggs, and olives, making rows of each ingredient. Drizzle with vinaigrette and toss to combine.
If packing for lunch, assemble the salad into lunch containers. Divide the dressing between 4 lidded sauce containers and pack with the salads.