I did a google search for rhubarb salsa, and found this one at many recipe sites:

Rhubarb Salsa recipe

1 cup granulated sugar
1/4 cup water
1 tablespoon finely shredded orange peel
6 cups rhubarb, sliced 1/2 inch thick
1/2 cup green bell pepper, diced
1/4 cup sweet onions, finely chopped
1/3 cup red onion, finely chopped
1 jalape o pepper, seeded and minced
2 tablespoons honey
2 tablespoons lemon juice
1 teaspoon fresh ginger, grated

In a medium, nonstick saucepan, combine the sugar, water and orange peel. Bring to a boil over high heat. Add the sliced rhubarb and reduce the heat to medium. Simmer gently until the rhubarb is tender, about 20 minutes. Remove from the heat and allow to cool to room temperature. When cool, transfer mixture to a food processor fitted with a steel blade, or to a blender and process until smooth. Scrape the pur e into a large bowl and add the remaining ingredients. Mix well. Serve chilled or at room temperature.

Yields about 4 cups.

Then, I found this technique for canning rhubarb. Perhaps you can use this canning technique by first following the rhubarb salsa ingredients:

Title: Canning rhubarb
Categories: Canning, Fruits, Check
Yield: 1 Servings
2 lb Makes 1 quart
You'll need about 1/2 to 1 cup of sugar for each quart of rhubarb. The
exact amount depends on the sweetness of the rhubarb and your taste.
If you prefer, can it with a minimum amount of sugar, and add the
sugar to taste when you serve it. You'll need the basic equipment and
a large bowl.

1. Choose tender, nicely colored stalks, Discard leaves.
   
2. Wash rhubarb well, trim off ends, but don't peel.
   
3. Cut stalks into 1 inch lengths.
   
4. In a large bowl, mix 1/2 to 1 cup sugar with each quart of cut
   rhubarb. Let stand 3 to 4 hours for juice to develop.
   
5. Organize and prepare equipment and work area.
   
6. Heat rhubarb and any juice left in bowl to boiling. Pack into hot
   jars to within 1/2 inch of tops. If you run out of syrup, use boiling
   water to fill the jars to within 1/2 inch of tops of jars.
   
7. Run a slim, non metal tool down along the inside of each jar to
   release air bubbles.
   
8. Add additional syrup or boiling water, if necessary, to fill to
   within 1/2 inch of tops of jars.
   
9. Wipe tops and treads of jars with a damp clean cloth.
   
10. Put on lids and screw bands as manufacturer directs.
    
11. Process in a boiling water bath for 10 minutes.
    
12. Follow basic steps for boiling water bath canning, 10 through 19.

Canning rhubarb plain and canning salsa are not the same as in this recipe low-acid ingredients like peppers and onion have been added. That lowers the pH and requires additional acid to compensate. I doubt the limited amount of lemon juice is sufficient.

There's no reason why rhubarb couldn't be substituted in this recipe for a peach salsa as the pH of rhubarb is lower than that of peaches (higher-acid). However, I think one of the reasons you don't see canning recipes for rhubarb salsa is that the texture suffers with canning and odds are you'll end up with a chunky rhubarb sauce.

Peach Salsa
Recipe By :Katie
Serving Size : 0 Preparation Time :0:00
Categories : Preserving
Amount Measure Ingredient -- Preparation Method
-------- ------------ --------------------------------
6 cups peaches -- diced
1 1/4 cups red onion -- chopped
4 jalapeno peppers -- chopped
1 red bell pepper -- chopped
1/2 cup chopped fresh cilantro -- loosely packed
1/2 cup white vinegar
2 tablespoons honey -- or sugar
3 cloves garlic -- finely chopped
2 teaspoons cumin
1/2 teaspoon cayenne
Simmer for 5 minutes. Pack into hot jars and process in a boiling water bath for 10 minutes (0-1000 ft.), 15 minutes (1001-6000 ft.), and 20 minutes (above 6000 ft.).
Katie

Carol