Bring a large pot of well-salted water to a boil. Add pasta, then cook until al dente.
Drain pasta in a colander, then rinse with cold water. Drain well.
While pasta is cooking, place almonds in a small skillet over medium heat. Cook until lightly browned and toasted (about 5 minutes), stirring frequently.
Let almonds cool slightly, then transfer to a food processor. Add serrano pepper and garlic. Pulse until finely chopped.
Roughly chop cilantro and parsley, then add to food processor, along with olive oil, lemon juice, and salt. Process pesto until smooth. Taste and add more salt, if desired.
Transfer cold pasta to a large bowl. Add pesto and gently toss to coat.
Place chopped onion in a fine mesh strainer, then rinse with cold water. Drain well.
Add onion to pasta, along with tomatoes, bell pepper, black beans, corn, olives, and queso fresco. Mix well, then adjust seasoning to taste with additional salt, if necessary.
Serve at room temperature or chill until ready to eat. Enjoy!
This pasta salad can be served hot, if you prefer. To do so, prepare pasta as directed and saute veggies in a little olive oil. Before draining pasta, reserve ½ cup pasta cooking water. Drain pasta, but do not rinse. Return to pot, then mix with pesto and other ingredients, adding just enough pasta cooking water to create a cohesive sauce.Feel free to add (or substitute) other veggies, such as diced avocado or thinly sliced zucchini. You could also swap roasted vegetables for the raw ones called for in the recipe.Can't find serrano peppers? Substitute a jalapeño or ¼ to ½ teaspoon cayenne.Not a cilantro fan? You can make the pesto with all parsley, or you can use a vinaigrette dressing instead. The Chili-Lime Vinaigrette from my Mexican Kale Salad would be delicious (I'd recommend doubling the ingredients).Skip the cheese to make this pasta salad vegan.