In a large bowl, combine the chickpeas, lentils, and edamame.
Add the red onion, cucumber, cherry tomatoes, and parsley.
In a small bowl or jar, whisk together the olive oil, lemon juice, and Dijon mustard until well combined.
Pour the dressing over the salad and toss until everything is nicely coated.
Season with salt and black pepper to taste.
Divide into containers if meal prepping. Keep refrigerated.