1. Peel and pit the avocado, then dice the flesh. Wash, deseed, and slice the peppers and tomatoes.
2. Wash and finely chop the cilantro. Drain the sardines and roughly crumble them with a fork.
3. In a salad bowl, mix the quinoa, tomatoes, peppers, cilantro, corn, and sardines.
4. In a bowl, whisk together the oil and vinegar, season with salt and pepper. Pour into the salad bowl and toss to combine well.
5. Divide into bowls and sprinkle the diced avocado on top.
6. Serve.