Place the first four ingredients into a small bowl and whisk to dissolve the wasabi. Preheat the oven to 400° to 425°. Place the asparagus spears on a baking sheet and evenly brush the water/shoyu/oil/wasabi mixture over the asparagus. Bake for about 15 minutes until tender. Remove, place on a serving platter and sprinkle with a pinch of sea salt if desired.
Variation: place the seasoned spears on a hot grill and grill for 2 to 3 minutes. Turn and grill another 2 to 3 minutes or until tender. They can also be broiled in a similar manner on a baking sheet.
Per serving - 7 calories, 1 g fat (64% calories from fat), 0 g protein, 0 g carbohydrate, 0 g fiber, 0 mg cholesterol, 103 mg sodium