Cabbage-Cilantro Slaw: Combine cabbage and cilantro in a large bowl.
In a small bowl, whisk together rice vinegar, soy sauce, lime juice and grape seed oil. Just before serving, pour the vinaigrette over the cabbage mixture and toss lightly. Will keep refrigerated in an airtight container for 2 days.
Sloppy Joes: Heat a large, heavy frying pan on medium-high. Add grape seed oil and swirl the pan to spread the oil. Add onions, garlic, ginger, celery and sambal oelek and sauté, stirring often, until onions are translucent, about 5 minutes. Add ground beef and ground pork and use a wooden spoon to break meat into small pieces. Cook, stirring frequently, until meat is no longer pink, 6-8 minutes.
Pour off and discard any fat from the meat (don't skip this step -- skim fat). Add hoisin sauce, tomatoes and lime juice, then season with salt and pepper. Reduce the heat to medium-low and simmer for 20-25 minutes, stirring occasionally.
Preheat the oven to 375°F.
Cut the buns in half, place them on a baking sheet and warm for 2 minutes, or until very lightly toasted.
Arrange the bottom halves of the buns on individual plates. Spoon about 2/3 cup of the Sloppy Joe mixture on top of each bun, then cover with 2-3 tablespoon of cabbage-cilantro slaw. Finish with the top halves of the buns. Serve immediately.