Char the skins of the poblano chiles by placing them over a gas burner or under a hot broiler with the oven door slightly cracked. Turn the chiles until the skins are black. Remove and cool the chiles in a tightly covered bowl, then peel and finely chop or process into coarse puree in food processor.
Heat extra-virgin olive oil over medium-high heat and add zucchini, onions, garlic, hot pepper, cumin, coriander, thyme, oregano, salt, and pepper, stir frequently for 10 minutes. Add in the tomato paste, and stir 1 minute more. Deglaze the pan with beer, stir in poblanos and beans and about half of the stock, bring to a bubble then reduce heat and simmer 10 to 15 minutes to combine flavors. Cool completely, cover and store for make-ahead meal. Reheat over medium heat.
While the chili reheats make the rice. Melt the butter in a saucepot over medium heat and add the rice, toast a minute or 2, then stir in 1 1/2 cups stock, bring to a boil, reduce the heat and cook covered, over low heat 15 minutes.
To food processor, add the spinach, cilantro, if using, and a little salt, and pulse into a fine paste. Stir the paste into the rice after 15 minutes. Turn off the heat, cover the pot and let the rice stand another 5 to 10 minutes. Fluff with a fork and serve in shallow bowls with zucchini chili and toppings of choice to garnish.