Heat a large, cast-iron skillet over medium-high heat with olive oil, 2 turns of the pan. Add chorizo to skillet and cook to render fat and brown. Remove from the skillet to a serving platter with a slotted spoon.
While the chorizo is browning, halve lemon and place in the skillet cut-side down to caramelize; remove. Add zucchini and cook to tender-crisp, 4-5 minutes. Remove to the same serving platter as the chorizo.