Step 1

Heat oil in a 10-inch wok or skillet over medium-high heat until shimmering. Add curry paste and cook, stirring constantly and pressing curry paste against bottom of pan until fragrant, about 30 seconds.

Step 2

Add green beans and increase to high. Cook, stirring and tossing constantly until beans are just beginning to turn tender-crisp, about 1 minute. Add chicken, 2 teaspoons fish sauce, sugar, and oyster sauce. Stir to combine.

Step 3

Cook until beans are tender-crisp and chicken is barely cooked through, about 1 minute longer. Taste sauce and add more fish sauce if desired. Thin with water until sauce barely coats all the meat and vegetables but is not soupy. Transfer to a serving platter and serve.