Watermelon, Black Bean and Corn Salsa

• 1 can corn kernels, rinsed and drained
• 1 can black beans, rinsed and drained
• ½ medium purple or white onion, coarsely chopped
• 1 to 2 jalapeno peppers, chopped
• 1 clove garlic, minced
• 1 teaspoon ground cumin
• 1  teaspoon chili powder
• 2 tablespoon salad oil (such as canola or olive)
• 1 lime, juiced
• 1 ½ cups watermelon, chopped (with seeds removed)
• Optional:

            Fresh cilantro, chopped

            Cucumbers, diced

            Avocado, diced