Wash potatoes to remove any dirt. Place potatoes in a large pot and cover with cold water. Bring to a rolling boil, add sea salt, reduce heat to medium low and simmer for 15 to 20 minutes until just tender. Drain and allow to cool for five to 10 minutes.
In a large bowl, combine boiled potatoes, onions, garlic, olive oil, vinegar and parsley and season with cayenne pepper, black pepper and sea salt. Mix well to evenly coat and season the potatoes and onions.
Preheat grill to medium high, approx. 450–550F.
If you have a grill basket, transfer seasoned potatoes and onions to the basket. This makes grilling easier since you will only have to turn the basket to grill all the pieces, instead of turning them one by one. Grill potatoes and onions for 10 to 15 minutes, turning occasionally until they are lightly charred and tender.
Transfer pieces to a large mixing bowl. Add the gherkins, black olives, sundried tomatoes, green onion and chopped parsley.
In a small bowl, whisk together the olive oil, vinegar, mustard and honey. Season to taste with coarsely ground black pepper and sea salt.
Pour dressing over the grilled potato mixture and gently toss to evenly coat. Add goat's cheese. Serve immediately.