Prepare Potatoes: Peel, wash, and pat dry 1 kg of waxy potatoes. Cut into 1/2 inch (1.5 cm) bite-sized pieces. Place potatoes in a stock pot in a flat layer and cover with just enough water to barely cover them. Season generously with sea salt. Bring to a boil over high heat.
Boil Eggs: Place 4 eggs in a saucepan and cover with water just enough to barely cover them. Bring to a boil over high heat. Once boiling, cover with a lid and turn off the heat. Let eggs sit for 10 minutes to become perfectly hard-boiled.
Cook Potatoes: Boil potatoes for 15 to 20 minutes until just cooked through but still al dente. Test by piercing with a toothpick; it should go in with some resistance. Avoid overcooking to prevent potatoes from breaking apart.
Cool Potatoes: Drain potatoes in a colander and rinse under cold water to stop cooking and cool to room temperature. Shake off excess water and transfer potatoes to a large bowl.
Prepare Salad Ingredients: Peel and finely chop the hard-boiled eggs. Add eggs to the bowl with potatoes. Add 1 medium sliced onion, 2 roughly chopped roma tomatoes, 1/3 cup (60 g) corn kernels, and 1 cup (120 g) pimento-stuffed Spanish green olives. Season with sea salt and freshly cracked black pepper.
Make Dressing: In a small bowl, whisk together 4 tablespoons (60 ml) extra virgin olive oil, 1 tablespoon (15 ml) white wine vinegar, finely grated or chopped 1 clove garlic, a pinch of sea salt, and freshly cracked black pepper until well combined.
Combine and Serve: Pour the dressing over the potato salad and gently mix until everything is well combined. Serve at room temperature or chilled. The salad can be stored in the fridge for 3 to 4 days.