In steam-proof dish or glass pie plate, stir together the lemon juice, ginger, soy sauce, sugar and cornstarch. Add chicken; stir to coat. Let stand at room temperature for 20 minutes.
Place dish with chicken and marinade on rack over 1 inch of water in wok or very large, deep skillet with lid. Heat water to a simmer over medium heat. Cover tightly; steam 5 minutes. Turn off heat and uncover. With tongs, turn chicken over. Cover and steam over medium heat until chicken is opaque, another 5 minutes.
Meanwhile, cook linguine in a large deep pot of lightly salted boiling water until al dente, firm yet tender. Drain well.
In large skillet, heat oil over medium heat. Add garlic; saute for 1 minute. Add pepper flakes and tomatoes; cook until tomatoes just start to break up, about 3 minutes. Add linguine and salt; toss to mix.
Place romaine on plates. Top with chicken and sauce. Divide linguine among plates. Garnish with scallions, cilantro and beans.