Start by washing and thoroughly drying your greens using a salad spinner or clean kitchen towels. Dice tomatoes into bite-sized pieces, removing excess seeds if they're particularly juicy. Slice cucumber into half-moons and julienne the red onion into thin strips.

Whisk together olive oil, lemon juice, Dijon mustard, and minced garlic in a small bowl until emulsified. Season with salt and freshly cracked black pepper, tasting as you go.

Place mixed greens in a large serving bowl, then layer tomatoes, cucumber, bell pepper, and red onion on top. If using fresh corn, blanch kernels for 2 minutes in boiling water for easier digestion, though raw works perfectly fine. Drizzle half the dressing over vegetables and toss gently.

Crumble feta cheese over the dressed salad and tear fresh basil leaves by hand rather than cutting them. Add remaining dressing only if needed. Taste and adjust seasoning before serving immediately.