1 medium onion, coarsely chopped
2 Tbsp tamarind concentrate
2 clove garlic, coarsely chopped
2 dried chipotle chiles, stems and seeds discarded
¾ cup golden raisin
¼ cup tomato paste
¼ cup agave syrup, see note
½ tsp pure chili powder
salt and freshly ground black pepper
4 skinless 4 ounce salmon fillets, halved crosswise
12 thin slices of whole wheat toast
¼ cup mayonnaise
1 cup arugula leaf
1 4 large slices of beefsteak tomato
1. In a saucepan, heat the oil. Add the onion and cook over moderate heat until softened. Add the tamarind, garlic, chipotles, raisins, tomato paste, agave and chile powder. Bring to a boil and simmer over low heat until thick, 20 minutes. Let cool, then puree in a blender. Season with salt and pepper.
2. Set the salmon in a large, shallow dish and season with salt and pepper. Coat with 1/2 cup of the sauce; refrigerate for 1 hour.
3. Light a grill and oil the grates. Grill the salmon over high heat, turning once and basting with another 1/2 cup of the sauce, until just cooked through, 4 minutes.
4. For each club, use 3 slices of toast; spread each with 1 teaspoon of mayonnaise and layer with the arugula, tomato and fish.