Immediately postworkout some guys love eating gummy bears or white bread with jelly. During this anabolic window your looking for an insulin spike/quick carbs to help replenish your muscles and help shuttle protein to them. Personally postworkout I take HydroWhey w/ .5scoop Dextrose & .5scoop Maltodextrin. Thats 30g protein w/ 50g carbs. Your wanting a 2:1 ratio postworkout carbs:protein. The carbs help protein synthesis and this is a crucial time frame to help your body recover/grow. After my shake I wait 45min-1hr then have a meal. My meal typically consists of brown rice, chicken breast, corn, black beans, a lot of peppers, garlic powder/cayenne powder. I have been eating that for months and never really gets old.
You were asking about tuna, whey, and brown rice postworkout. Well whey is good being that it'll take roughly 45minute to absorb and if you use ON Whey it has Hydrosolized peptides in its for faster absorbtion. The tuna is a good source of protein, low carbs, moderate cals, some healthy fats. The brown rice would not be a good choice of carbs postworkout. Yes brown rice is a good complex carb but not want you want postworkout. It will take too long to digest and will not help shuttle the protein through your body. Leave the brown rice for a meal later on.
My suggestions would be- Whey, buy some dextrose, white bread, jelly, gummy bears, any simple carb that isn't too unhealthy for you.