Put the fish cubes in a bowl. Soak eight 8-inch wooden skewers in water for at least 30 minutes.
Meanwhile, make the pesto: Put the almonds and garlic in a food processor and pulse until finely chopped. Add the mint, parsley and lemon zest and pulse until finely ground. Transfer the mixture to a small bowl and whisk in the olive oil; loosen with 1 tablespoon water, if needed. Season the pesto with salt, pepper and the red pepper flakes, if using. Pour about one-third of the pesto over the swordfish and toss to evenly coat. Reserve the remaining pesto for serving. Refrigerate the swordfish for at least 30 minutes and up to 4 hours.
Preheat a grill to medium high. Skewer 3 or 4 chunks of swordfish on each skewer. Grill, turning once, until just cooked through, 2 to 3 minutes per side. Drizzle the skewers with the reserved pesto and serve with lemon wedges.
Photograph by David Malosh
Recipe from Endless Summer cookbook. Copyright (c) 2015 by Katie Lee. Published by Stewart, Tabori & Chang, an imprint of Abrams.