In a large bowl, toss together the chayote, cabbage, carrots, jicama, scallions, cumin, coriander and 2 teaspoons salt. Let the flavors combine while you make the dressing for the slaw.
To a food processor, add the crema, orange juice, cilantro, lime juice, agave, hot sauce, garlic, avocado and jalapeno. Process until completely smooth; season with salt. Refrigerate in an airtight container until ready to serve; the dressing can be made 1 day in advance.
When ready to serve, toss the dressing with the vegetables. Garnish with the reserved scallions and serve immediately.