In a blender, working in batches, puree the tomatoes, cucumbers, bell and poblano peppers, and onion, transferring the pureed mixture to a bowl.
Stir in the lime juice, oil, 1 ¼ teaspoons salt, and ½ teaspoon pepper. Refrigerate until chilled, 15 to 20 minutes.
Divide the soup among bowls and top with the sour cream, pepitas, and cilantro. Serve with the tortillas (if desired).