Steam potatoes until tender. Clean mussels and open by placing in a large pan with a tight fitting lid and heating. Remove mussel meat from shells. Make vinaigrette by infusing saffron from stamens in 1/2 tablespoon hot water. Rub a bowl with the crushed garlic and add oil, vinegar, salt and pepper to taste and saffron infusion. Mix well. While potatoes are still hot, dress liberally with the vinaigrette. Assemble the rest of the ingredients and toss all together.