Rinse chicken and pat dry with paper towels. Cut chicken crosswise into 1/4 inch wide slices.Combine onion, anchovy paste, garlic, and crushed red pepper in a food processor or blender; process until smooth. Set aside.Heat the wok over high heat about 1 minute or until hot. Drizzle oil into the wok and heat 30 seconds. Add chicken and stir fry until chicken is no longer pink in the center. Remove chicken to a large bowl.Reduce heat to medium.Add onion mixture to the wok and stir fry 1 minute. Add mushrooms and corn; mix well. Add soy sauce and sugar; stir until sugar dissolves. Return chicken to the wok. Stir fry until heated through. Add basil; toss gently to combine.Line a serving platter with lettuce leaves. Spoon chicken mixture onto lettuce.Garnish, if desired.