Heat a wok or large skillet over medium-high heat. Add 1 tablespoon oil to pan; swirl to coat. Add 2 cups rice cakes; stir-fry 3 minutes or until blistered, turning to brown on both sides. Remove rice cakes from pan; place in a large bowl. Add remaining 1 tablespoon oil; swirl to coat. Add remaining 2 cups rice cakes; stir-fry 2 minutes. Add green onions to pan, and stir-fry for 1 minute or until rice cakes are blistered, turning to brown on both sides. Remove rice cake mixture from pan; add to cooked rice cakes.
Add pork to pan; sauté for 4 minutes or until browned, stirring to crumble. Stir in chopped onion and salt; sauté 3 minutes, stirring occasionally. Add garlic; sauté 30 seconds, stirring constantly. Stir in cornstarch. Gradually add stock; bring to a boil. Stir in soy sauce and sambal; cook for 1 minute, stirring frequently. Divide rice cake mixture evenly among 4 shallow bowls; top each serving with 3/4 cup pork mixture. Serve with lime wedges.