Drain and rinse one can of black beans and one can of corn thoroughly. Place them in a large mixing bowl.
Dice the red and green bell peppers, tomatoes, red onion, and avocado into small, bite-sized cubes for an even mix of textures and flavors.
Finely chop the parsley and add it to the bowl. If using, drain and flake in the canned tuna or your choice of protein.
In a small bowl or bottle, combine 1/4 cup extra virgin olive oil, the zest and juice of a lemon, one minced garlic clove, 1 tsp chili powder, 1/2 tsp salt, 1/2 tsp cumin, and a few drops of Tabasco. Shake or whisk until well blended.
Pour the vinaigrette over the salad ingredients and gently mix until everything is evenly coated. Serve fresh and enjoy!