In a food processor, combine the mint, parsley and chives with the shallot, lemon juice, sherry vinegar, crushed red pepper and a pinch of salt and process until finely chopped.
Add the olive oil and process the salsa verde until smooth.
Transfer half of the salsa verde to a small bowl.
Transfer the remaining salsa verde to another bowl and stir in the paprika and cumin.
Add the lamb pieces and turn to coat thoroughly.
Thread the lamb onto 8 long skewers and refrigerate for at least 2 hours or up to 24 hours.
Light a grill or preheat a grill pan.
Grill the lamb skewers over high heat, turning them occasionally, until the lamb is lightly charred in spots, about 6 minutes for medium meat.