Prepare the ingredients as instructed.
Prepare Split Pea Soup: In a slow cooker, combine split peas, onion, carrot, celery, garlic, chicken broth, dried thyme, black pepper, and bay leaf. Cover and cook on low heat for 6 - 8 hours until peas are tender. Season with additional salt and pepper as needed. Remove bay leaf before serving.
Mix the water and cucumber slices. Refrigerate to infuse.
Make the Grilled Ham and Cheese: Butter one side of each slice of bread. Heat a skillet over medium heat.
Place two slices of bread, butter side down, in the skillet. Top with cheese and ham, then the remaining slices of bread (butter side up).
Grill until the bread is golden and the cheese is melted, flipping once. Cut in half.
Serve the split pea soup with half grilled ham and cheese, cucumber water, and watermelon.