In a large bowl, combine olive oil, red wine vinegar, soy sauce, hot sauce and mustard. Add the prepared tempeh and mix to evenly coat. Set aside.
In a small pan over medium heat, add your sliced onions with 1 tsp of olive oil. Cook for 5 minutes, stirring occasionally. Once the onions have turned slightly brown, add the beer and continue to cook until the onions are dark brown and softened. Set aside.
Heat up your barbeque to medium-high heat. Add the tempeh to the grill and cook for 5 minutes on each side, basting the tempeh in the leftover marinade each time you flip them. Once lightly charred on all sides, remove and build your dogs!
Top your dogs with the onions, and your favourite hotdog toppings.