Warm the oil in a large pot or Dutch oven over medium heat. Add the onion and bell pepper. Cook, stirring occasionally, until softened, about 5 minutes.
Add the garlic, ginger, curry powder, thyme, allspice, and optional minced hot pepper. Stir continuously for 30 seconds, until fragrant. Do not let the spices scorch.
Add the potatoes, chickpeas, diced tomatoes with their juices, coconut milk, vegetable broth, salt, and black pepper. Stir well, scraping the bottom of the pot.
Bring the stew to a gentle simmer. Partially cover, reduce the heat to medium-low, and cook until the potatoes are fork-tender and the broth has thickened slightly, about 18 to 20 minutes. Stir once or twice during cooking.
Stir in the spinach until just wilted. Remove the pot from the heat and stir in the lime juice. Taste and add more salt if needed.
Serve warm with rice, cilantro, and scallions if desired.