Grate the hard-boiled eggs into a mixing bowl using a cheese grater.
Stir in the tarragon, capers, mustard, garlic, olive oil, and vinegar; season and chill.
Butterfly the chicken breasts and cut each half lengthways into four strips.
Coat the chicken strips with dried herbs, spices, white pepper, and 30 ml of oil.
Preheat a hot grill and thread the chicken meat lengthways onto 16 wooden skewers.
Place the skewers on a foil-lined grill tray and drizzle with a little olive oil.
Grill for 4-5 minutes, then turn and grill for another 3-4 minutes.
Spoon the salsa over the skewers and serve with a final twist of black pepper.