Preheat the oven to 350°F. Peel and mince garlic. Peel and halve the red onion, then mince one half and thinly slice the other. Trim, deseed, and mince the jalapeno. Chop the tomato. Drain and rinse the black beans.
Add the sliced onion to a small saucepan with just 3 tbsp apple cider vinegar (reserve the remainder for the beans), turbinado sugar, a pinch of salt, and ¼ cup water. Bring onions to a boil, reduce heat, and simmer for 8 to 10 minutes, stirring occasionally. Transfer pickled onions to a bowl and place in the refrigerator to cool.
Add basmati rice, 1 cup water, and a pinch of salt to another small saucepan and bring to a boil. Cover, reduce heat to low, and cook until rice is tender and water is absorbed, about 12 to 15 minutes. Turn off heat and leave covered for 10 minutes; then fluff rice with a fork.
Place a large skillet over medium-high heat with 1 tsp olive oil. Add half of the minced onion, minced garlic, Mexican oregano and chili spice, and cook until onions are soft; 3 to 5 minutes. Add the black beans and ½ cup water, vegetable broth, remaining apple cider vinegar, to the skillet. Lower heat and cook until hot, about 5 to 6 minutes. Mash half of the beans with the back of a fork and cover to keep warm.
Wrap corn tortillas in foil and warm in the oven. Halve and remove the pit from the avocado. Scoop the avocado flesh into a medium bowl and mash with the back of a fork. Add the remaining minced red onion, chopped tomato, and as much or as little of the minced jalapeno as you’d like. Mix guacamole well to combine and season with salt.
Remove tortillas from the oven and divide between large plates. Top each tortilla with cooked rice, Cuban-style black beans, guacamole, and pickled red onions.