Open the canned goods and drain them. Rinse the beans and chickpeas then drain.

Combine the red beans, chickpeas, corn, chopped parsley, sliced cucumber, and diced onion in a large mixing bowl. Set this aside.

In a separate small bowl, whisk together the olive oil, lemon juice, Dijon mustard, sugar, garlic, and a pinch of salt and black pepper. Whisk until combined, taste, and add additional seasoning if needed.

Now pour the dressing over the vegetables and toss to combine. Taste and add additional salt and pepper if desired.

Chill until ready to serve.