Rinse and cook the quinoa according to package instructions. Once cooked, set aside to cool.

In a mixing bowl, combine flaked mackerel, diced cucumber, halved cherry tomatoes, and diced red onion.

In a separate bowl, whisk together lemon juice, capers, olive oil, minced garlic, salt, and pepper to create the dressing.

Once the quinoa is cool, add it to the bowl with the vegetables and mackerel. Pour the dressing over and toss to combine.

Serve immediately or chill in the fridge for 30 minutes for enhanced flavors.