Heat oil in a skillet over high heat. Cook and stir onion until slightly softened, about 1 minute. Add snow peas, sugar snap peas, and bok choy; stir-fry until bright green, about 8 minutes. Stir in curry powder. Cook, stirring occasionally, until flavors combine, 8 to 10 minutes. Stir in feta cheese.
Push snow pea mixture into a mountain in the center of the skillet; let cook for 3 minutes. Push mountain down with your spatula and cook for 3 to 5 minutes more.