Place the watermelon, tomatoes, red onion, almond meal, red wine vinegar, 1 tablespoon of olive oil, salt, and garlic in the bowl of a food processor or in a blender pitcher. Purée until smooth, then refrigerate for at least 1 hour (and up to two days). Stir and adjust seasoning if needed. Stir, then pour into bowls and serve topped with a drizzle of olive oil and crumbled feta.