In food processor, combine pecans, parsley, garlic, zest of lemon and 1/8 teaspoon salt. Process briefly until chunky puree. Set aside.
Rinse and pat-dry scallops. Lightly season with salt. Roll scallops in flour, then toss in colander to shake off excess flour. Heat oil in large skillet over high heat. When hot (but not smoking) add scallops and sauté quickly, tossing frequently until golden and nearly cooked through—about 4 to 5 minutes. Reduce heat to low. Add pecan mixture and cook 2 minutes. Remove to serving plate and sprinkle with lemon juice.