Bibim Naengmyeon (Korean Spicy Cold Noodles)

Name: Bibim Naengmyeon (Korean Spicy Cold Noodles)
Cuisine: Asian, Korean
Ingredients: 1/2 cucumber (120g); 4.2 oz (120g) Korean radish (or daikon) (optional); 3.5 oz (100g) thinly sliced beef for hot pot; 1/4 Korean pear (or Asian/Nashi pear, red apple), to garnish; 2 packs naengmyeon noodles (300g) (or somyeon noodles); 1-2 hard-boiled eggs, to serve; Generous pinch of toasted sesame seeds, to garnish; 1 cup (240ml) white vinegar; 4 tbsp sugar; 1 tsp salt; 1 tsp hot mustard (optional); 4 cups (960ml) water; 1 tbsp Korean beef stock powder (dasida); 1 tsp sugar; 1 tsp soy sauce; 1/4 Korean pear (or Asian/Nashi pear, red apple) (140g); 1/4 yellow onion (70g); 2 green onions (30g); 2 cloves garlic; 2 tbsp water; 3 tbsp Korean chili paste (gochujang); 3 tbsp sugar; 4 tbsp soy sauce; 3 tbsp Korean chili pepper powder/flakes (gochugaru); 3 tbsp white vinegar; 1/2 tbsp Korean beef stock powder (dasida); 3 tbsp toasted sesame oil