Chef Eric Ripert shows Martha how to make hamachi tandoori, a truly elegant appetizer.
Season hamachi fillets with salt and pepper. Rub one side of each fillet with garlic; sprinkle both sides with dried thyme and tandoori powder. Place oil in a medium shallow bowl. Add fillets and turn to coat.
Preheat a medium nonstick skillet over medium-high heat. Remove fish from marinade; reserve marinade. Add fish to skillet and cook, turning once, until just lightly golden and warm, but still rare in the center, 1 to 2 minutes per side.
Slice fish into 1/4-inch slices and divide slices among 4 serving plates. Place a 1 1/2-inch ring mold on one of the plates, opposite the fish. Fill 3/4 full with cucumber salad. Carefully remove the mold and repeat process with remaining three plates.
Place mache in a small bowl and lightly season with salt and pepper. Add sherry vinaigrette and toss gently. Place on top of cucumber salad. Squeeze lemon over fish and serve with reserved marinade, if desired.