Soak beans with a good amount of water overnight. Once soaked, drain and rinse the beans. Place the beans in a large pot and cover with fresh water. Add 1 tsp. salt to the cooking water. Place on the stovetop and bring to a boil, then reduce to a simmer. Simmer for 1 hour, or until you reach desired tenderness. Stir the beans a few time so they don’t stick to the bottom. Drain out most of the water. You should leave about 1/2 inch of water at the bottom. Add minced garlic, ginger, soy sauce and maple syrup. Cook for a couple minutes, stirring constantly, then remove from heat, cover and set aside.
Using a mandolin or sharp chef’s knife slice daikon radish and cucumber into paper thin rounds. Add to a bowl with with a squeeze of lemon and salt. Set aside.
Heat oil and garlic in a pan. When garlic starts to sizzle, about 30 seconds add mushrooms and saute 3 to 4 minutes, turning until lightly browned. Season with salt to taste.
Set a large pan over medium-low heat. Arrange 2-3 tortillas in a single layer. Flip them after 30 seconds or so. As they come off the stove, wrap them in a clean tea towel. Repeat with a second batch. Fill each taco with black beans and mushrooms. Top with radish and cucumber and a drizzle of hot sauce, if desired.