Cut goat cheese log into 8 rounds. Gently press each round to ½-inch thickness on a baking sheet lined with parchment and freeze 20 minutes.

Place flour in a small bowl. Whisk together the egg and milk in a second small bowl. Combine the panko, salt, and pepper in a third small bowl. Dredge goat cheese rounds in flour, dip in egg mixture, and dredge in panko mixture until coated. Place on a plate, and chill until all goat cheese rounds are breaded.

Heat oil in a large, non-stick skillet over medium until hot. Add goat cheese rounds to skillet, and cook until golden brown on each side, 3 to 4 minutes total. Remove to a paper towel-lined plate.

Arrange salad greens on a serving platter; top with strawberries, cucumber, onion, and goat cheese croutons. Drizzle with vinaigrette.

Toss together strawberries, sugar, vinegar, salt, and pepper in a bowl. Let stand 15 minutes.

Transfer the strawberry mixture to a blender, and process until smooth, about 30 seconds. Turn blender on low, and gradually add olive oil in a slow, steady stream.

Return mixture to bowl, and whisk in poppy seeds. Whisk vinaigrette just before serving.