Preheat the grill to 425˚F. Wipe the cleaned grates with 2 tablespoons of avocado oil. This can easily be done by drizzling the oil on a paper towel then rubbing the towel on the hot grates.
Prep the guajillo chili and beans: If using the guajillo pepper, bring a quart of water to a boil, then remove from heat and add 1 guajillo chili. Cover with a lid and steep for 8 minutes. Wearing gloves, remove the chili from the water and remove the stem and seeds. Slice the guajillo into thin ribbons and reserve.
Warm 1 ½ cups of refried beans in a small covered pot over low to medium heat on the stove. Stir every 3 minutes until warmed through and check for seasoning.
Prep the veggies: Slice 1 zucchini and 1 yellow squash into ½ inch rounds, core 1 orange or red bell pepper and slice into thirds, and slice 1 red onion into ½ inch rounds.
Grill the veggies in a single layer, working in batches if needed. Everything should be tender and slightly charred, but not burnt. You’ll season the veggies once they have finished grilling.
Zucchini and squash: 2-3 minutes on both sides.
Bell pepper: start skin side down, 3-4 minutes on both sides.
Red onion: 3-4 minutes on both sides.
Once cooked, cut the peppers and onions into bite size pieces then transfer to a bowl along with the squash and zucchini. Season with ½ teaspoon of berbere seasoning, sea salt, freshly cracked black pepper and drizzle with 2 tablespoons of extra virgin olive oil. Toss gently and reserve.
Warm 8 corn tortillas on the grill, just until tender and malleable. Transfer to a platter and spread a spoonful of refried beans on top of each tortilla. Then divide the grilled veggies, sliced guajillo and ¼ bunch cilantro leaves between the tortillas. Serve with a ¼ cup of Yucatecan salsa on the side.