Prep: 1. Heat grill to medium-high. 2. Cut watermelon into bite sized pieces. 3. Mince mint. Slice cucumber into half moons. Juice lime. 4. Slice onion and rub with 1 tablespoon canola oil. Make 1. Mix together pork, soy sauce, garlic, and 1-2 tablespoon Sriracha in a large bowl until just combined. Form into four patties. 2. Grill onion and burgers 4-6 minutes per side. 3. Meanwhile, toss watermelon, cucumber, mint, 1 tablespoon lime juice, 1 tablespoon oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper in a medium bowl. 4. Mix together ketchup and 1 tablespoon Sriracha in a small bowl. 5. Stack ketchup mixture, lettuce, burgers and onions between buns (if using). Serve with watermelon salad.
Serve with buns or wrap in lettuce leaves for a low-carb option. If you prefer to grill these just preheat the grill before beginning prep, then when the grill is hot, grill burgers for 5-6 minutes per side, or until done through.