Season your Tri-tip with the Y'all Purpose seasoning. Preheat your smoker to 225°F.
Place the tri-tip roast in the indirect heat zone and smoke for 1 1/2 to 2 hours, or until the internal temperature reaches 135°F.
In a food processor, pulse the parsley, cilantro, garlic, red wine vinegar, olive oil, salt and pepper until finely chopped. This is your chimichurri.
In a small bowl, mix the mayonnaise and sriracha hot sauce.
Toast the sandwich rolls and spread spicy mayo on one side and chimichurri on the other.
Thinly slice the tri-tip against the grain and place it on the sandwich rolls. Serve immediately. Enjoy!