For the marinade: Mix the oil, lime juice, orange zest and juice, garlic, onions, chili powder, cumin and salt in a bowl until combined. Adjust seasoning if necessary. Transfer the marinade into a large freezer bag. Add the chicken and marinate in the fridge for 2 to 4 hours.
For the carrot slaw: In a mixing bowl, combine the carrots, vinegar and agave. Toss to coat and season with salt and pepper. Set aside.
For grilling: Heat a grill pan to medium-high heat and lightly coat with 1 tablespoon of the canola oil. Pull the chicken out of the marinade and grill each side until dark grill marks form, 6 to 8 minutes a side. Then let rest for at least 5 minutes.
Toss the scallions with the remaining 1 tablespoon canola oil and season with salt and pepper. Grill until charred on all sides. Chop and set aside.
For the sandwich build: Spread 1 tablespoon of the Poblano Crema on the bottom of a roll. Then add some sliced chicken, Charred Salsa, carrot slaw and charred green onions. Cut on the diagonal and serve with additional salsa on the side.
Peel, stem and seed the poblanos. Place in food processor and pulse until smooth. Add the Mexican crema, agave and lime juice, and season with salt and pepper. Pulse until just combined. Scoop into a bowl and spread on everything.
Heat a large grill pan to medium-high heat. Add the tomatillos, garlic, tomatoes, onion, ancho and poblano chiles. Char on all sides until blackened in parts, removing the charred vegetables and chiles to a cutting board once blackened. Depending on their size, each vegetable will char at a different rate.
Place the charred ancho chile into a small bowl and pour enough hot water to cover it. Allow to sit until the chili is softened, 8 to 10 minutes. When softened, remove the stem and seeds.
Remove the stem and seeds from the charred poblano as well as the stem and skins from the charred garlic cloves and onion quarters.
Put the soaked ancho and poblano chiles, tomatillos, garlic, tomatoes, onion, cilantro, agave and lime juice into the bowl of a food processor and blend until mostly smooth. Season with salt and pepper to your heart's content.