Preheat the oven to 400. Break down the head of broccoli by peeling the stem and slicing it into 1/4 inch pieces. Cut the florets into 1/2 inch pieces. Toss the broccoli well with olive oil and salt and roast until starting to caramelize but still bright green, 15 minutes.
While the broccoli roasts, prepare the black bean hummus. Combine black beans (with the liquid), sesame seeds, lemon juice, garlic, tahini, sugar and salt in the food processor and blend until smooth.
Prepare the shallot vinaigrette. Combine shallot, olive oil and vinegar in the blender and blend until smooth.
Prepare the General Tso's sauce. Combine cornstarch, ginger, garlic, soy sauce, honey, vinegar, sesame oil and chili flakes in the blender and blend until smooth. Transfer to a small pot and cook over medium heat until slightly thickened, 5-7 minutes.
Once the broccoli has been roasted, add it to a large saute pan over medium heat. Add the shallot vinaigrette a few tablespoons at a time and taste until the broccoli is sweet and tangy. Cook the broccoli until softened, 5 minutes.
Heat the taco shells. Wrap the soft flour tortillas in a damp kitchen towel and microwave for 1 minute, and heat the hard shells in the oven until crispy. 5-7 minutes.
Assemble your tacos. Spread a layer of black bean hummus on a flour tortilla and then wrap it around the hard taco shell (the hummus will act as a glue). Then fill the taco with broccoli and feta cheese. Top with General Tso's sauce and crispy fried onions