Preheat oven to 375 degrees. Place beets, water, and 1/4 teaspoon salt in a baking dish. Cover with parchment, then foil, and bake until beets are tender when pierced with the tip of a small knife, 45 to 55 minutes. Let stand until cool enough to handle. Peel and quarter beets, and place in a small bowl. Toss with 1 teaspoon oil.
Combine lentils and sliced ginger in a medium saucepan, and cover with water by 2 inches. Bring to a boil. Reduce heat, and simmer gently. Cook, stirring occasionally, until lentils are tender, about 20 minutes. Drain; discard ginger. Transfer to a large bowl, and stir in 1/2 teaspoon salt.
Combine remaining teaspoon salt and the grated ginger, onion, vinegar, and honey, and let stand for 15 minutes. Whisk in remaining tablespoon oil and the coriander. Pour over lentils, and toss to coat. Season with pepper. Stir in chopped mint and cilantro. Arrange beet wedges on top of lentils. Garnish with herbs, and serve immediately.