Place the peeled and diced potatoes in a large pot and cover with cold water. Add 1 tablespoon of salt to the water.
Bring the water to a boil over medium-high heat, then reduce to a simmer. Cook the potatoes for 12-15 minutes, or until they're tender enough to pierce easily with a fork but still hold their shape.
Drain the potatoes thoroughly in a colander, then spread them on a baking sheet to cool and dry for about 15 minutes.
While the potatoes cool, prepare the dressing by whisking together mayonnaise, olive oil, lime juice, Dijon mustard, 1/2 teaspoon salt, and 1/4 teaspoon black pepper in a large bowl until smooth.
Add the cooled potatoes to the dressing bowl, along with the red onion, green onions, and cilantro. Gently fold everything together using a rubber spatula to avoid breaking the potatoes.
If using, carefully fold in the chopped hard-boiled eggs and sliced olives.
Taste the salad and adjust the seasonings as needed, adding more salt, pepper, or lime juice to achieve your desired flavor balance.
Cover the bowl and refrigerate for at least 30 minutes, though 2 hours is ideal to allow the flavors to meld together.
Before serving, gently stir the salad again and taste once more for seasoning adjustments.
