Rinse the mixed greens thoroughly in cold water and spin or pat dry until crisp. Halve the cherry tomatoes. Peel (if desired) and slice the cucumber into half-moons about 1/4-inch thick. Thinly slice the red onion and separate into rings.

Assemble salad

Place the dried mixed greens in a large salad bowl. Scatter the cherry tomatoes, cucumber slices, and red onion over the greens. Sprinkle the crumbled feta and chopped toasted walnuts evenly on top. If using optional add-ins, arrange sliced avocado and sliced grilled chicken over the salad and sprinkle the chopped fresh herbs.

Lemon-Honey Vinaigrette

In a small bowl or jar, combine fresh lemon juice, honey, Dijon mustard, minced garlic, sea salt, and black pepper. Whisk briefly to dissolve the honey and salt.

While whisking constantly, slowly drizzle in the extra-virgin olive oil until the dressing is fully emulsified and slightly thickened. Taste and adjust seasoning: add more salt, pepper, or lemon to preference. If too tart, add a little more honey (1/2 tsp increments).

If making ahead, cover and refrigerate up to 3 days. Shake or whisk well before using; let come to room temperature if chilled so oil doesn't solidify.

To Serve

Right before serving, drizzle about 3 to 4 tablespoons of the Lemon-Honey Vinaigrette over the assembled salad (start with less; you can always add more). Gently toss the salad with salad tongs to coat the greens and ingredients evenly.

Taste and adjust: add additional vinaigrette, salt, or pepper to taste. Serve immediately on chilled plates for best texture.