Make Cucumber Tomato Salad now: crisp cucumbers, sweet tomatoes, fresh mozzarella, and bright Italian dressing.
In a medium bowl combine the olive oil, red wine vinegar, lemon juice, finely grated Parmesan, dried parsley, dried basil, dried oregano, garlic powder, salt and pepper. Whisk vigorously until the Parmesan is distributed and the dressing looks glossy and slightly grainy from the cheese. Set the bowl aside and give it a quick whisk again right before using so the oil and acids re-emulsify; this dressing is intentionally simple and slightly loose in texture.
Bring a large pot of salted water to a boil and drop in the asparagus pieces for a very quick 2-minute blanch—bright green with tender stems but still slightly crisp. Immediately drain and rinse under cold water to arrest cooking; the asparagus should feel snappy and show tiny water beads from the chill, ready to hold their verdant color in the salad.
In a large shallow wooden bowl combine the quartered English cucumber slices, halved cherry tomatoes, thin red onion slivers, blanched asparagus, fresh corn kernels, and halved mozzarella balls. Drizzle the reserved Italian dressing over the mixed vegetables and gently toss until the dressing lightly coats surfaces—visible glossy droplets on tomato flesh, tiny grated Parmesan clinging to cucumber skin, and a scattered sheen on mozzarella. Cover the bowl with plastic wrap and chill in the refrigerator for at least 30 minutes so flavors meld while textures stay crisp.

Just before serving, fold in the chopped Haas avocado gently so large creamy chunks remain distinct against the crisp vegetables. Serve immediately—avocado will brown if left exposed—so only add it to portions being eaten. Give the salad a gentle stir each time before serving because the dressing will separate over time; you’ll see thin pools of oil at the bottom and a renewed glossy coating once stirred.
This salad is best enjoyed within 12 hours for peak cucumber crunch, though it will keep in the refrigerator up to 48 hours. If storing, omit the avocado until serving. When you retrieve the salad from the fridge, stir thoroughly to redistribute the dressing (it does not contain an emulsifier), and expect slightly softened cucumbers over time but still bright, herb-flecked flavor.