Place the broccoli in a steam basket and steam it over salted boiling water until it turns vibrant green, about 2-3 minutes.
Immediately plunge the broccoli in icy cold water and move it around delicately until it's completely chilled. Don't skimp on the ice here, the faster your broccoli gets cold, the crunchier and greener it will remain.
Transfer the cold broccoli to a colander and let it drain until it's pretty dry. At this point, you can put the broccoli in the refrigerator until you are ready to eat it.
Heat the olive oil in a large skillet set over medium heat; add almonds and sesame seeds and cook until golden and fragrant, about 1 minute.
Lower heat to medium-low, add broccoli, lemon zest, ginger, sesame oil, fish sauce, pepper flakes, salt and pepper and continue cooking until heated through, about 3-5 minutes.