01 - Preheat a grill or grill pan to medium-high heat.
02 - Brush the corn lightly with olive oil and grill, turning occasionally, until charred in spots and tender, about 8-10 minutes. Let cool, then cut the kernels from the cobs.
03 - Cook orzo in salted boiling water according to package instructions until al dente. Drain and rinse with cold water to stop cooking.
04 - In a blender or food processor, combine scallions, dill, olive oil, lemon juice, white wine vinegar, Dijon mustard, garlic, salt, and pepper. Blend until smooth and creamy. Adjust seasoning as needed.
05 - In a large bowl, combine cooked orzo, grilled corn kernels, cherry tomatoes, cucumber, red onion, and chopped dill. Toss gently.
06 - Pour the scallion dill dressing over the salad and toss to coat evenly. Top with crumbled feta if desired. Serve chilled or at room temperature.