Rinse the cooked brown lentils thoroughly under cold running water and drain well in a colander. Meanwhile, cut the quarter cucumber and half ripe avocado into equal cubes. Roughly chop the unsalted walnuts with a chef's knife and finely chop the fresh dill.
Make the dressing by whisking the cold-pressed flaxseed oil, juice of half a lemon and dijon mustard together in a small bowl until smooth. Take a large bowl and mix the drained lentils, handful of rocket and cucumber cubes together well.
Add the avocado cubes and roughly chopped walnuts to the lentil mixture. Pour the prepared dressing over the ingredients in the bowl. Gently toss the salad so the avocado keeps its structure and everything is evenly coated with the dressing.
Divide the salad over a plate or shallow bowl. Garnish by sprinkling the tablespoon of hemp seeds and finely chopped fresh dill over the top last. Serve immediately.