Place crab in a large bowl. Add the celery and green onions; toss gently to combine.
In a separate bowl or large measuring cup, whisk together the mayonnaise, lemon juice, vinegar, dill, Old Bay, and sugar. Add the mayonnaise mixture to the crab mixture; toss to coat. Taste and season with kosher salt and pepper. Cover and refrigerate until ready to serve, or enjoy right away. Stir in additional mayo, to taste, if you prefer a more moist crab salad.
Butter the cut sides of the hot dog buns. Griddle, buttered-side down, until golden brown. Fill each bun with crab salad. Garnish with additional dill, chives, or freshly-chopped parsley.
