Instructions

Preheat a grill to medium heat.
In a medium saucepan, bring 1 3/4 cups water to a boil (and add a pinch of kosher salt). Once boiling, add the brown lentils, cover and reduce heat. Simmer covered for 20 to 25 minutes, until most of the water has been absorbed.
Turn off the heat, then stir in the olive oil, ketchup, chili powder, cumin, paprika, garlic powder, onion powder, dried oregano, kosher salt, black pepper, and red pepper flakes.
Meanwhile, cut the squash, zucchini and onion into thin strips. Place them in a bowl; toss with enough olive oil to coat, and sprinkle with kosher salt and pepper. Grill the vegetables until tender, for about 5 minutes, turning frequently.
Make the pickled red onions and the sauce of your choosing (Chili lime sour cream, Cashew cream, Chipotle sauce, or Creamy cilantro sauce).
To serve, add lentils to a warmed tortilla; top with grilled vegetables, pickled onions, and chili lime sour cream.