Cook the potatoes according to package instructions and place in a large bowl reserving the herb seasoning packet for later.
While the potatoes are cooking, boil the green beans until bright green in boiling water, about 3-4 minutes, adding the corn kernels 1 minute before the cooking time is over. Drain the beans and corn then add to the bowl with the potatoes.
Add the tomatoes to the bowl.
In a small bowl, whisk together olive oil, lemon juice, salt, pepper and reserved garlic-parsley herb packet. Drizzle on top of the vegetables and toss well