In a large pot of boiling, salted water, cook the beans until crisp-tender, about 5 minutes. Drain, rinse with cold water and drain again; set aside.
In a saucepan, combine 1/2 cup water, the brown sugar, fish sauce, garlic and lemon peel. Season with pepper and simmer over medium-low heat until reduced to a thick syrup, about 12 minutes. Add the shrimp and cook over high heat, stirring, until pink, about 3 minutes.
Add the cooked beans to the shrimp and sauce, and toss to coat. Serve over the rice.