For the rice, place it in a small pot with the chicken stock, turmeric, garlic powder and salt. Stir, cover with a lid and cook on low heat for about 15 minutes, or until rice is fluffy.
For the salad, take two chopsticks and place a cucumber on top. Make multiple slices at a 45-degree angle, flip over and make multiple slices straight across. Repeat with the remaining cucumbers. Add the salt between the slices and let sit for 15 to 20 minutes to release some moisture.
Rinse the cucumbers, then dry with a paper towel and place in a large bowl. Add the garlic, gochugaru, sesame oil, rice vinegar, soy sauce, brown sugar and sesame seeds and carefully combine without breaking the cucumbers. (The cucumbers will get softer the longer they sit, so if you like them really crunchy, serve them as soon as possible.)
For the beef, in a large bowl, mix together the sliced beef, lemongrass, shallots and garlic. Mix in the fish sauce, brown sugar, soy sauce and 1 tablespoon of the avocado oil, then let marinate for 10 to 15 minutes.
Heat ½ tablespoon of the oil in a large skillet over medium-high heat. Add half the beef, laying the slices flat in the pan, and cook 1 to 2 minutes on both sides, then transfer to a plate. Repeat with the remaining ½ tablespoon oil and the beef. Serve with the rice and salad.