Boil the meat well and cut into pieces lengthwise. If the beef is fibrous, it can simply be disassembled into fibers.
Cut the onion into quarter rings.
Cut the cucumber into strips.
Try slicing tomatoes the same way as a cucumber.
Chop the greens, do not grind them into granules.
Mix everything, add salt, add ground black pepper. I usually don't fill this salad with anything, so everyone's tastes are different, even in our family, everyone refills it on their own. Just serve mayonnaise separately, mix vegetable oil with lemon juice separately (you can add a little mustard).