caldo de res recipe

2 pounds beef shank, bone-in, cut into pieces - 8 cups water - 1 large onion, quartered - 3 cloves garlic, minced - 2 teaspoons salt (or to taste) - 2 ears corn, cut into thirds - 3 carrots, cut into large pieces - 2 zucchinis, cut into large pieces - 2 potatoes, peeled and cut into large chunks - 1/2 head green cabbage, cut into wedges - 2 chayotes, peeled and cut into large chunks (optional) - 1 bunch fresh cilantro, chopped - 1 lime, cut into wedges (for serving) - Corn tortillas (for serving)