Heat 2 tablespoons oil in heavy large non-stick skillet over medium-high heat. Season fish with salt and pepper. Add to skillet and saute until just cooked through, turning occasionally, about 8 minutes. Transfer fish to plates. Reduce heat to medium-low. Add remaining 2 tablespoons oil, garlic and thyme and cook until garlic is golden brown, stirring occasionally, about 4 minutes. Add lemon juice and simmer until liquid thickens slightly, about 1 minute. Season to taste with salt. Spoon sauce, garlic and thyme over fish. Sprinkle with chives and serve.