Chop the broccoli into small florets. Slice the outer layer of the main stem and discard. Use the fresher interior. Chop into bite-sized pieces. Remove the ends of the green beans and halve them.
Blanch the broccoli and green beans in boiling water for 5 mins. Rinse under cold water and set aside.
Add the chillies, ginger and garlic to a small blender jar. Pulse until coarsely chopped. You don’t want a paste here, just small bits.
Heat the oil in a large wide pan. Add the chilli-ginger-garlic and cook for 1 minute. Add the oyster sauce and sugar. Cook for 2 mins.
Tip in the cooked broccoli and beans and toss to coat. Taste and adjust seasoning. Serve hot with sesame seeds sprinkled over.